By Tom O’Connor, Newsweek–

Recent U.S-led coalition airstrikes targeting forces supportive of Syrian President Bashar al-Assad killed a number of Russians fighting on behalf of the Syrian leader, according to associates of the slain fighters and independent researchers.

Maxim Buga, a Cossack community leader in the Russian exclave of Kaliningrad, told Reuters Monday that local Vladimir Loginov was among “dozens” of Russian fighters killed by U.S.-led coalition forces, which clashed with pro-Syrian government forces on February 7 near the eastern Syrian town of Khusham, Deir Ezzor province.

Alexander Averin, spokesperson for the far-left party The Other Russia, told the outlet that one of its members, Kirill Ananiev, had also been killed in the incident, which the U.S.-led coalition and pro-Syrian government forces have accused one another of provoking, as a new front threatened to open in the war-torn country.

Conflict Intelligence Team, a Moscow-based military research site, has also highlighted other alleged casualties as Russia distanced itself from the violence and the presence of its private military contractors in Syria.

Citing researchers on Twitter, Conflict Intelligence Team identified additional Russian casualties, including Alexey Ladygin from the city of Ryazan and Stanislav Matveev and Igor Kosoturov from the town of Asbest. The group said both Metveev and Kosoturov may have fought alongside pro-Russia separatist rebels in eastern Ukraine prior to joining the fight against the Islamic State militant group (ISIS) and other insurgents challenging Assad’s rule in Syria.

The group also said that Loginov appeared to have joined the Wagner Group, a private paramilitary company, before traveling to fight in Syria. Last October, ISIS released a videoshowing two Russian-speaking men the militants claimed to have captured, and subsequent research showed the two men were likely Wagner Group members fighting in Syria.

“While the total number of ‘Wagner’ operatives killed in Coalition airstrikes is unlikely to ever be established, it is beyond doubt that this incident indeed took place. It is notable that the posts about their deaths emerged rather quickly—relatives and colleagues often learn of Russian mercenaries’ deaths weeks or even months after the fact,” the Conflict Intelligence Group wrote on Facebook Monday.

“Russia’s Ministry of Defense again distanced itself from those killed, stating there were no Russian soldiers in the area and the ‘local militia’ acted without coordination with the Russian command,” it added.

The exact death toll of the clashes have been disputed, but it may have risen as sporadic fighting reportedly continued in the days since. In a statement, the U.S. military claimed the strikes were a response to an “unprovoked attack” on the Pentagon-backed Syrian Democratic Forces, a mostly Kurdish coalition of Arabs and ethnic minorities, by pro-Syrian government forces.

In a statement sent to Newsweek on Wednesday, a coalition spokesman said the coalition could “not speculate on the exact make-up of the Syrian pro-regime forces who conducted the attack,” nor “the number of Syrian pro-regime force casualties at this time.” However, Reuters quoted one unnamed U.S. official as saying that “the coalition and its local allies killed more than 100 of them.”

Russian and Syrian officials have condemned the attack as an “act of aggression.” The Russian Defense Ministry said that pro-Syrian government forces were conducting a surveillance mission near the oil fields when they suddenly came under Syrian Democratic Forces attack, followed by U.S. coalition airstrikes. It said 25 Syrian militia fighters had been injured, while the official Syrian Arab News Agency said scores had been killed. The U.K.-based, pro-opposition Syrian Observatory for Human Rights said Thursday the dead had reached 48 among pro-government forces “of Syrian and non-Syrian nationalities.”

Neither pro-government or pro-opposition sources mentioned whether Russian nationals were among the pro-Syrian government forces—which comprise a wide alliance of local and foreign militias—some of which received support from Iran. The Russian Defense Ministry, however, has denied the presence of the Russian military in the area.

Both the Syrian military, backed by Russian air cover and allied militias, and the U.S.-backed Syrian Democratic Forces have all but defeated ISIS in Syria, but unprecedented tensions on the eastern front have threatened to work in the jihadis’ favor. A joint Turkish and Syrian rebel offensive launched last month in the northwest and Israeli air raids on Syrian military defenses near Damascus have also complicated efforts to defeat ISIS.

Despite recent setbacks, Russian presidential spokesperson Dmitry Peskov hailed Wednesday new talks with fellow Assad supporter Iran and pro-opposition Turkey. He criticized the U.S.’s approach, however. Russia—along with Syria and Iran—has accused Washington of shielding ISIS and other jihadi groups in order to prolong its military presence, something the U.S. has denied.

“As you may know, the Russian president has for the past few weeks maintained regular contacts with his Turkish and Iranian counterparts. This work will go on. It is expected to provide significant support for further peacemaking activity within the framework of U.N. efforts

[in Syria],” Peskov said, according to the state-run Tass Russian News Agency.

“As for the United States’ assistance in stabilizing the situation in Syria and advancing the search for a political and diplomatic solution, it has been in short supply,” he added.