TEL AVIV—As Israel advances its invasion of southern Lebanon, its troops are finding large troves of Russian weapons, confirming longstanding suspicions in Israel that Hezbollah is enhancing its fighting capacity with the help of sophisticated Russian arms.
Some of the weapons, which include modern Kornet antitank missiles manufactured as recently as 2020, were sent to southern Lebanon in recent years from Russian stockpiles in neighboring Syria, according to Syrian security officials and an Arab official. Russia has long provided arms to Syria’s military, as well as controlling its own warehouses in the country.
Although Israeli military leaders knew Hezbollah possessed some Russian-made arms, their inability to access parts of southern Lebanon since fighting a war with Hezbollah in 2006 made it hard to know the full extent of the militant group’s capabilities. Russian weapons Hezbollah was known to possess tended to be less sophisticated, with some dating back to the Soviet era.
The weapons Israel is finding now are newer, more advanced, and present in larger numbers than expected by military analysts. The arms have significantly bolstered Hezbollah’s ability to fight back after Israeli airstrikes decimated its top leadership, they say. Antitank weapons such as the Kornet have been among the most effective weapons in Hezbollah’s arsenal, and have been used to kill numerous Israeli soldiers.
The weapons discoveries have also added to fears in Israel that Russia may be deepening its relationship with Hezbollah, despite Moscow’s longstanding assertions that it doesn’t take sides in conflicts between Israel and its neighbors.
“Israel needs to be more assertive and defend its interests,” said Arkady Mil-Man, a former Israeli ambassador to Russia. “We must explain and convey to the Russians that we will no longer stand any assistance to Hezbollah and Iran that could hurt Israelis,” said Mil-Man, now a senior researcher at the Institute for National Security Studies in Tel Aviv.
The Russian government and the Syrian foreign ministry didn’t return requests for comment. The Israeli prime minister’s office declined to comment.
Israel’s foreign minister, Gideon Sa’ar, highlighted Russia’s leverage over the militant group when he said recently that Israel hopes Russia will help enforce any agreement to disarm Hezbollah by preventing weapons smuggling from Syria to Lebanon.
“The principle that Hezbollah won’t be able to arm again or get new weapons systems or take them into Lebanon and to renew the threat to the extent it was before the war is vital to the success of any arrangement in Lebanon,” he said. “The Russians are present in Syria. If they agree with the principle, they can contribute to achieving this objective effectively.”
Israel has long sought to maintain good relations with Russia, in part to avoid conflict in Syria, where Russia has a military presence and Israel conducts military strikes aimed at stemming the flow of weapons to Hezbollah.
But Russia’s stance in the region has been changing since Russia’s war with Ukraine began in 2022, analysts say, with Moscow more aggressively seeking to challenge the U.S. and its allies wherever possible.
Russia provided targeting data for Yemen’s Houthi rebels as they attacked Western ships in the Red Sea earlier this year, The Wall Street Journal has reported, and is considering delivering antiship missiles to the Houthis, U.S. officials have said. The Journal has also reported that Wagner Group, the Russian paramilitary organization, planned to provide an air-defense system to Hezbollah, though it is unclear if the delivery was made.
Since Hamas’s deadly Oct. 7, 2023, attack on Israel, Russia has hosted top Hamas leaders multiple times in Moscow. Russia said it held those talks to help broker a reconciliation between Hamas and Fatah, a rival Palestinian group which administers parts of the West Bank and wants a say on the authority that will rebuild Gaza.
Russia’s cooperation with Iran has also deepened, with Iran providing Moscow with drones and ballistic missiles for Russia’s use in the war in Ukraine. The same drones used against Ukraine are now being used by Hezbollah against Israel with deadly results, according to an Israeli security official.
Russia’s involvement with Syria deepened after Syria’s civil war began in 2011, and the Russian military intervened to aid President Bashar al-Assad. Russia sent weapons that were stockpiled by Syrian forces and maintained its own warehouses of weapons in the country.
Around 2015, Russians began fighting on the ground in Syria alongside Hezbollah soldiers, who had also come to Assad’s aid. That led to closer relations between the two, the Syrian security officials and the Arab official said, making it easier for Hezbollah to draw on Russian stockpiles in Syria whenever it needed more weapons, especially antitank, antiaircraft and antiship missiles, these officials said.
The Journal wasn’t able to determine how often Hezbollah obtained weapons this way. Traditionally, a large share of Hezbollah’s weapons have come from Iran, its primary backer, and were Iranian-made.
A Journal reporter viewed some of the Russian weapons during a tour of Israel’s National Munition Disassembly Lab, where materials seized from southern Lebanon are taken for examination.
In addition to the Russian Kornets, the weapons included other Russian guided antitank missile systems, including Metis, Konkurs, Fagots and Saggers. All were found less than a kilometer inside southern Lebanon, above ground and underground in Hezbollah bunkers, an Israeli major who heads the disassembly lab said.
Approximately 60% to 70% of the weapons seized in the initial days of Israel’s invasion were Russian, the Israeli major said. Since then, reservists who spoke to the Journal said they continue to find many Russian weapons inside Lebanon.
The major said he wasn’t sure how Hezbollah obtained the weapons or got training for them.
Israel invaded southern Lebanon in late September to push Hezbollah back from border areas and end a daily barrage of missile attacks Hezbollah launched a year ago in solidarity with Palestinians in Gaza.
Markings on some of the weapons viewed by the Journal appeared to confirm that they made their way from Russia to Hezbollah via Syria. One case of rockets found in southern Lebanon had a label in Russian that said the weapons were sent from Russia to Syria’s ministry of defense. Not all of the weapons had such markings.
Michael Cardash, the former deputy head of Israel’s national police bomb disposal division, who remains a consultant to the Israeli police, said the markings on the Kornets confirmed the models were Russian rather than their Iranian copy, the Dehlavieh.
It was unclear when all the weapons were sent to Lebanon, though the major who heads the disassembly lab said that some were made in 2020. Others, such as Saggers, appeared to be much older and had labels showing they were manufactured in the 1980s.
Fabian Hinz, a military research fellow at the International Institute for Strategic Studies think tank in London, said the availability of reliable, short-range missiles such as the Kornet has been critical to Hezbollah, enabling it to pursue a more efficient campaign against Israel than Hamas, which has only had access to less-reliable Iranian copies.
The Kornet, along with two other antitank Russian missiles seized by the Israeli military, has appeared dozens of times in Hezbollah videos of attacks against Israel since Oct. 7, 2023, said Adam Rousselle, a researcher at Militant Wire, a network of experts that examines weapons used by nonstate actors.
An Israeli staff sergeant who is part of a medical evacuation team fighting in Lebanon said that the most effective method of killing Israeli soldiers he had so far seen was antitank missiles or Kornets which could be shot from 7-to-8 kilometers away. While Hezbollah has been weakened by Israeli attacks, it remains far more formidable than Hamas, in part because of its more-advanced arsenal, he said.
Since Israel began its ground operation ִagainst Hezbollah in Lebanon, 43 of its troops have been killed there.
Israeli officials have previously said that removing the threat of antitank missiles on Israeli communities, along with pushing back Hezbollah’s elite Radwan unit north of the Litani River, would be two prime goals of a land operation. An earlier Kornet attack in April, which Hezbollah said targeted surveillance equipment in the Israeli-occupied Shebaa Farms, severely injured six Israeli soldiers, Israel’s military said at the time.
Some analysts and Israeli officials are questioning Israel’s policies toward Russia, arguing that Moscow has made its position clear by militarily supporting the country’s enemies. Unlike most Western countries, Israel has offered only limited nonmilitary support for Ukraine in its war against Russia, a strategy analysts say is driven by a desire not to anger Moscow.
“We need to sober up from this approach,” said Carmit Valensi, a senior researcher at the Institute for National Security Studies, a Tel Aviv-based think tank. “It’s no longer just Russian support for the axis of resistance” that is unconnected to Israel. “We are meeting this in the battlefield and it is extracting casualties.”
Write to Anat Peled at anat.peled@wsj.com, Summer Said at summer.said@wsj.com and Benoit Faucon at benoit.faucon@wsj.com