U.S. Strikes Killed Scores of Russia Fighters in Syria, Sources Say

• American, rebel forces repel attack by mercenaries in the east
• The 200-plus deaths dwarf official Russian toll in the war

U.S. forces killed scores of Russian mercenaries in Syria last week in what may be the deadliest clash between citizens of the former foes since the Cold War, according to one U.S. official and three Russians familiar with the matter.

More than 200 contract soldiers, mostly Russians fighting on behalf of Syrian leader Bashar al-Assad, died in a failed attack on a base held by U.S. and mainly Kurdish forces in the oil-rich Deir Ezzor region, two of the Russians said. The U.S. official put the death toll in the fighting at about 100, with 200 to 300 injured, but was unable to say how many were Russians.

The Russian assault may have been a rogue operation, underscoring the complexity of a conflict that started as a domestic crackdown only to morph into a proxy war involving Islamic extremists, stateless Kurds and regional powers Iran, Turkey and now Israel. Russia’s military said it had nothing to do with the attack and the U.S. accepted the claim. Defense Secretary Jim Mattis called the whole thing “perplexing,” but provided no further details.

President Vladimir Putin’s spokesman, Dmitry Peskov, declined to comment on reports of Russian casualties, saying the Kremlin only tracks data on the country’s armed forces. Putin talked with U.S. President Donald Trump by phone Monday, but the military action in Syria wasn’t discussed, he said.

“This is a big scandal and a reason for an acute international crisis,” said Vladimir Frolov, a former Russian diplomat and lawmaker who’s now an independent political analyst. “But Russia will pretend nothing happened.”

Putin, with Iran’s help, turned the tide of the seven-year war by committing air- and manpower to buoy Assad’s beleaguered forces in 2015, quieting U.S. calls for the Syrian leader’s immediate removal. With Islamic State, which once controlled large swaths of Syria, now largely defeated, rival powers and militias are fighting in various combinations to fill the vacuum. Russia, Iran, Israel and Turkey have all had aircraft shot down in or near Syria this month.

Artillery, Tanks

Last week’s offensive began about 8 kilometers (5 miles) east of the Euphrates River deconfliction line late Feb. 7, when pro-Assad forces fired rounds and advanced in a “battalion-sized formation supported by artillery, tanks, multiple-launch rocket systems and mortars,” Colonel Thomas F. Veale, a spokesman for the U.S. military, said in a statement.

The U.S., which has advisers stationed at the base alongside Syrian Democratic Forces troops, responded with aircraft and artillery fire.

“Coalition officials were in regular communication with Russian counterparts before, during and after the thwarted, unprovoked attack,” Veale said. No fatalities were reported on the coalition side and “enemy vehicles and personnel who turned around and headed back west were not targeted.”

Asked about the killing of Russian mercenaries in Syria, CIA Director Mike Pompeo told a Senate Intelligence Committee hearing in Washington Tuesday that he would leave specifics to the Pentagon but “we have seen in multiple instances foreign forces using mercenaries in battles that will begin to approach the United States.”

It’s not clear who was paying the Russian contingent, whether it was Russia directly, Syria, Iran or a third party. Reports in Russian media have said Wagner -- a shadowy organization known as Russia’s answer to Blackwater -- was hired by Assad or his allies to guard Syrian energy assets in exchange for oil concessions.

“No one wants to start a world war over a volunteer or a mercenary who wasn’t sent by the state and was hit by Americans,” Vitaly Naumkin, a senior adviser to Russia’s government on Syria, said in an interview.

The U.S. is in talks with Russia now in search of an explanation for what happened, said two administration officials who asked not to be identified discussing private conversations. 

The officials said the U.S. was puzzled because proper procedures had been followed -- American forces used the deconfliction line to get Russia’s go-ahead to defend coalition forces against the attackers. 

The officials also said it wasn’t clear whose fighters made up the attacking force. They said the deconfliction line was still operating and Russia so far hadn’t protested the decision to launch the air strikes.

Yury Barmin, a Middle East analyst at the Russian International Affairs Council, a think tank set up by the Kremlin, said Russia supports Assad’s efforts to reclaim the “crucial” eastern region of Deir Ezzor to help fund his national reconstruction and reconciliation plan, which the U.S. opposes.

Russia signed a “road map” agreement with Assad’s government last month to assist in rebuilding the nation’s electricity network. On Tuesday, Energy Minister Alexander Novak told reporters in Moscow that Russian companies are interested in contracts to help refurbish damaged oil pipelines and wells.

‘Illegal Presence’

While Russia’s Defense Ministry didn’t mention mercenaries in its statement, it did say 25 “Syrian” fighters were injured, without elaborating. It accused the U.S. of using its “illegal presence” in Syria as an excuse to “seize economic assets,” even as it kept lines of communication with the U.S. open.

Assad’s government in Damascus called the U.S. military action “barbaric” and a “war crime.”

The death toll from the skirmish, already about five times more than Russia’s official losses in Syria, is still rising, according to one mercenary commander who said by phone that dozens of his wounded men are still being treated at military hospitals in St. Petersburg and Moscow.

Most of those killed and injured were Russian and Ukrainian, many of them veterans of the separatist conflict in eastern Ukraine, according to Alexander Ionov, who runs a Kremlin-funded group that fosters ties to separatists and who’s personally fought alongside pro-government forces in Syria.

Grigory Yavlinsky, a longtime Russian opposition politician who helped steer democratic reforms after the collapse of the Soviet Union in 1991, called on the authorities to come clean about what happened.

“If there has been mass deaths of Russian citizens in Syria, then the relevant authorities, including the general staff of the Russian armed forces, have a duty to inform the country about this and decide who bears responsibility,” Yavlinsky, who is running against Putin in next month’s election, said on Twitter.