According to Reuters, Russia said only five of its citizens may have been killed in the battle.
Russian news media and social networks have published many reports about the fighting, describing how US aircraft decimated Russian private military contractors who sought to take control over an oil factory near Khusham.
The Kremlin did say that if any Russians died, "They are not connected to the armed forces of the Russian Federation". Still, her statement amounted to official recognition that the victims were part of the force that advanced on the US -backed fighters.
USA forces are "focused on" fighting Islamic State (IS) militants, he said, adding: "We're not looking for a fight with anyone else, but as Secretary Mattis said last week: 'If you threaten us, it will be your longest, and your worst, day'". "In eastern Syria, the Russian Ministry of Defense can say, 'We don't know they were doing this.' But it's very likely this had some kind of direction from higher-ups in the Kremlin".
In the February 7 clash, the US military said a battalion-sized formation backed by tanks and artillery attacked the USA -backed fighters and the USA responded by unleashing a broad range of air power.More news: Flu claims 2 more lives in Clark County
Bloomberg cited two of its Russian sources as saying that more than 200 mercenaries, a lot of them Russians, were killed, and The New York Times cited a Syrian military officer as saying about 100 Russians were killed. She said reports of tens or hundreds of Russian casualties were disinformation inspired by Russia's opponents.
The U.S. -backed Kurdish-led forces have been vying with Russian-backed Syrian troops reinforced by Iranian-supported militias for control of the oil-rich Deir el-Zour province. Both came out of Russian Federation. The wounded evacuated from Syria in the past few days have been shifted to four Russian military hospitals, according to five sources familiar with the matter.
Several hundred Russian mercenaries were involved in the battle over a Syrian oilfield near Deir Ezzor and came under attack from United States aircraft, possibly the first direct military confrontation between Americans and Russians since the Vietnam War. This was Moscow's first admission of non-military combat casualties. A Kremlin spokesman, asked about casualties, said he no information on any casualties. Some estimates place the number of Russian dead at 200.
"Obviously, the United States has some strategy, which, I think, is geared to keep its military presence in Syria forever", Lavrov added.