(CNN) — On September 19, the day Azerbaijan began its offensive in the majority Armenian region of Nagorno-Karabakh, Marut Vanyan heard an ominous noise in the sky over his hometown.

“I’m not a military expert,” Vanyan, a journalist, recalled. “But I heard very, very clearly… the roar above me. I’m sure it was a drone.”

Vanyan, a lifelong resident of Stepanakert, once Nagorno-Karabakh’s largest city, recognized the sound from 2020, when Azerbaijan waged a 44-day war for the territory and surrounding regions with the help of Turkish and Israeli weapons.

According to Leonid Nersisyan, a defense analyst and researcher at the Applied Policy Research Institute (APRI) Armenia, an independent think tank, it was the sound of Israel Aerospace Industries’ Harop, a loitering munition known for the piercing noise it produces as it descends on a target.

Azerbaijani forces used the Harop – often referred to as a “suicide drone” – and other Israeli drones throughout the war of 2020. CNN has contacted IAI for comment.

Though their relationship is relatively discreet, Israeli equipment makes up most of Azerbaijan’s arms imports, according to arms researchers. Azerbaijani officials touted Israel’s weapons as integral to their country’s success in Nagorno-Karabakh during the 2020 war.

Israel’s ‘fingerprints’

Now, as over 100,000 ethnic Armenians have fled Nagorno-Karabakh in the latest conflict there, Israeli-Azerbaijani ties have come under scrutiny, with an editorial in Israel’s most prominent left-wing newspaper Haaretz proclaiming that the country’s “fingerprints are all over the ethnic cleansing” in Nagorno-Karabakh.

“Drones were used constantly” in the 2020 war, as well as in this latest conflict, a former lieutenant colonel in the Artsakh Defense Army – the Armenian separatist republic’s military force in Karabakh - told CNN on the condition of anonymity. (Artsakh is the Armenian name for Nagorno-Karabakh and the self-proclaimed republic that existed there.)

Azerbaijan won the 2020 war in a little over a month, regaining much of the territory internationally recognized as part of Azerbaijan but populated and governed, until now, almost exclusively by ethnic Armenians, following the expulsion of ethnic Azeris in the late 1980s and early 1990s.

September’s battle barely took 24 hours, leaving the whole of Karabakh under the control of Azerbaijan after months of blockade. All of the roughly 120,000 ethnic Armenians in the territory have either fled to Armenia or are expected to flee, fearing full-fledged ethnic cleansing or mass atrocities, although Azerbaijan has insisted that it would respect their rights there.

Azerbaijan and Israel are close military partners. According to the Stockholm International Peace Research Institute (SIPRI), more than 60% of Azerbaijani weapons imports came from Israel between 2017 and 2020, making up 13% of Israeli exports during the same period. SIPRI research reveals that Azerbaijan purchased a wide variety of drones, missiles, and mortars from Israel between 2010 and 2020.

However, according to SIPRI senior researcher Pieter Wezeman, certain specifics are unknown about the extent of the ongoing Azerbaijani-Israeli weapons trade.

“We had quite some information before 2020 and then it stops,” Wezeman said. “And that doesn’t really make sense because in 2020 Azerbaijan used a significant amount of its equipment… Most likely they have continued their relationship with Israel, but that’s about as far as we know.”

Likewise, Haaretz reported in mid-September that the same company flew between Baku and Ovda less than a week before Azerbaijan began its latest assault in Nagorno-Karabakh. CNN reached out to the Azerbaijani Ministry of Defense and the airline in question, but did not receive a response. The Israeli Ministry of Defense, which oversees Ovda Airport, had no comment.

“We don’t know what was on board, but very likely it is something related to the military equipment that Israel already has supplied to Azerbaijan before,” Wezeman said.

Beyond guns and ammunition

The weapons trade between Israel and Azerbaijan mirrors their diplomatic relationship, once described in a leaked US diplomatic cable as “like an iceberg, nine-tenths of it… below the surface.” Despite decades of bilateral cooperation, Azerbaijan only opened an embassy in Israel this year.

But their ties go beyond guns and ammunition: OEC figures show that Israel bought 65% of its crude oil from Azerbaijan in 2021. The countries are also believed to share intelligence on Iran, Israel’s archenemy, with which Azerbaijan shares a border and which has a substantial ethnic Azeri population that constitutes the country’s largest minority. Azerbaijan has also reportedly allowed the Israeli spy agency Mossad to use it as a hub to spy on Iran. (The Israeli Ministry of Defense declined to comment on the matter.)

According to Efraim Inbar, an expert on Israel-Azerbaijan relations and president of the Jerusalem Institute for Strategy and Security, ties between the two have grown stronger since 2020.

In a recent interview with the Jerusalem Post, Armenia’s ambassador to Israel said Israeli weapons are being fired at “peaceful civilians” despite Israeli civil society being “very pro-Armenia in the case of Nagorno-Karabakh and recognition of the Armenian genocide.” (Israel’s government does not recognize the mass murder of Armenians by Ottoman forces during World War I as genocide, fearing damage to its relationship with Turkey, the successor state of the Ottoman Empire.)

Arms sales ‘good for Israel’

But there is little political opposition in the country to selling arms to Azerbaijan, Inbar said.

“Arms sales do not receive much publicity,” he added. “The contribution of Israeli drones to Azerbaijan’s war is well known, however. Israelis are proud of their weaponry. Arms sales are considered good for Israel.”

Yet despite their high visibility in Karabakh, the role of drones should not overshadow that of other Israeli weapons, according to Nersisyan, the defense analyst at APRI Armenia.

“People consider them to be some kind of a super weapon,” he said. “Of course, they are very important, but there are roles of other types of weapons.”

Among those are Israel’s LORA missiles, which Azerbaijan first purchased from Israel in 2017 according to SIPRI.

The question remains as to how far Israel is willing to go in supporting Azerbaijan in its conflict with Armenia. An ongoing border crisis between the two countries has resulted in Azerbaijani incursions into Armenian territory, and Azerbaijani troops currently occupy land well within Armenia’s borders in its southern Syunik province. Many in Armenia worry that an emboldened Azerbaijan will attempt to invade their country, which Azerbaijan denies. Some fears center around Nakhchivan, a landlocked exclave of Azerbaijan that borders Turkey and Armenia, and Baku’s desire for a transport corridor linking it with the rest of the country.

“Azerbaijan doesn’t have any military goals or objectives on the sovereign territory of the Republic of Armenia,” Hikmet Ajiyev, the foreign policy advisor to Ilham Aliyev, told Reuters on October 1.

Israeli ‘realpolitik’

Some in the international community are calling for action against Azerbaijan in the wake of the Armenian exodus from Karabakh. In the United States, where there is a large Armenian diaspora, nearly 100 members of Congress have called for sanctions on Baku, and lawmakers in the European Union have also called on the bloc to consider punitive measures.

Wezeman, the researcher at SIPRI, said Israel could come under pressure from its Western allies to reconsider arms sales to Azerbaijan.

“It will damage its relations with Azerbaijan, but at the same time, Israel will have to think about its relations with European states, which are more important partners.”

Efraim Inbar said Israel wants to keep its reputation of being a reliable supplier to Azerbaijan.

“In any case,” he added, “Azerbaijan is much more important for Israel than Armenia. It is realpolitik that drives Israeli foreign policy.”

The-CNN-Wire

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Azerbaijan and “brother ally” Turkey turned up the heat on embattled Armenia on September 25, hinting that they may be set to push hard for Yerevan to agree to a land bridge across Armenian territory that would link their two countries.

As Armenia struggled to deal with the mass exodus of ethnic-Armenians fleeing the Nagorno-Karabakh enclave in the wake of last week’s decisive one-day military offensive conducted by Azerbaijan, Turkey’s President Recep Tayyip Erdogan pointedly met Azerbaijani counterpart Ilham Aliyev for the opening of a newly modernised military installation in Azerbaijan’s Nakhchivan exclave—the territory holds great importance in that Baku wants to carve a land corridor across Armenia from the main part of Azerbaijan to Nakhchivan, which borders Turkey.

Azerbaijan and Turkey—which often refer to their two countries as “two states, one nation”—insist Armenia promised to accept such a corridor in the Russian-brokered ceasefire talks that ended the 44-day Second Nagorno-Karabakh War in late 2020, something that Yerevan denies.

At a joint news conference following their meeting, at which neither strongman took any questions, Aliyev lamented how Soviet-era authorities had decided that, part of what he said should have been territory belonging to the Azerbaijani Soviet republic, was land belonging to the Armenian Soviet republic.

"The land link between the main part of Azerbaijan and Nakhchivan was thus cut off," complained Aliyev, as reported by Reuters.

The corridor, if built, would stretch across Armenia’s southern Syunik province. Both Azerbaijan and Nato member Turkey refer to it as the Zangezur Corridor.

Addressing the UN General Assembly in New York on September 19, the very day Azerbaijan invaded ethnic-Armenian-controlled Karabakh, Erdogan referred to the desired land link, saying: "We expect a comprehensive peace agreement between the two countries [Azerbaijan and Armenia] as soon as possible and for promises to be quickly fulfilled, especially on the opening of the Zangezur corridor."

Aliyev has since the last Karabakh war occasionally become rather bellicose about his demand for the corridor. In 2021, he threatened to create it "whether Armenia likes it or not".

However, a big difficulty for Aliyev is that Nakhchivan and Syunik both border Iran and any land bridge would necessarily run parallel to the Armenian-Iranian border. Tehran has made it clear that it is staunchly opposed to any developments near its border that could interfere with its trade routes via Syunik and is clearly also greatly concerned that such a corridor would extend Turkey’s geopolitical heft across both the South Caucasus and Central Asia, which borders Azerbaijan. There were fresh reports this week in the Iranian media of Tehran beefing up its military deployments near Iran’s borders with Armenia and Azerbaijan.

Russia’s current stance on whether the corridor should be permitted by Armenia is not clear, but Moscow is engaged in an increasingly bitter spat with Armenia over Yerevan’s accusation that Russia has not lived up to its security commitments as Armenia’s strategic partner and the Armenian government’s newly expressed willingness to strengthen ties with the West.

Speaking after his meeting with Erdogan in Nakhchivan, where the pair also attended a gas pipeline groundbreaking ceremony, Aliyev—as reported by Turkish state-run news service Anadolu Agency—said: “[Azerbaijan and Turkey] want peace and stability in the region, not war”.

The meeting, however, has clearly sown plenty of anxiety.

Thomas de Waal, a senior fellow at think tank Carnegie Europe who specialises in Eastern Europe and the Caucasus, wrote on his X platform microblog that Azerbaijan and Turkey could present an ultimatum to Armenia over the corridor, saying: “Days after Azerbaijan's military takeover of Karabakh, Presidents Aliyev and Erdogan meet in Nakhchivan today and will very likely make ultimatums to the Armenian government to ‘open the Zangezur Corridor or else...’ 

“Can we be really going the world of 1918-21 when big powers try to use force to draw and redraw the map of the Caucasus? Let it not be so.”