Russia and U.S.-allied forces in Syria exchanged accusations that deaths within their ranks were caused by fire from the other side, adding to tensions as they wage separate campaigns within close proximity of one another.
Russian Deputy Foreign Minister Sergei Ryabkov asserted on September 25 that the United States was to blame for the death of a Russian general over the weekend, without providing evidence.
U.S. State Department spokeswoman Heather Nauert denied the accusation, saying on Twitter that claims the United States was complicit in the general's death had "no basis in fact."
Meanwhile, a spokesman for the U.S.-allied Syrian Democratic Forces (SDF) said Russian planes targeted SDF fighters in gas fields not far from the city of Deir al-Zor, killing one and injuring two of the fighters.
Russia denied the accusation and a spokesman for the U.S.-led coalition in Syria said that while rounds hit the SDF forces, it could not confirm that the fire came from Russian forces.
It was the latest of a series of accusations traded as Russian-backed Syrian troops and a U.S.-allied, Kurdish-led militia battle in close proximity to retake territory held by the Islamic State (IS) extremist group in eastern Syria near the Iraqi border.
In exchanges last week, each side accused the other of targeting and injuring their troops, but no deaths were reported.
Moscow and Washington held a first-ever meeting between their generals last week to try to prevent such accidental clashes, but reports this week of deaths in continuing clashes suggest the problem was not resolved and may be worsening.
Ryabkov and Colonel Ryan Dillon, a spokesman for the U.S. coalition, said military-to-military communications were continuing.
In the latest exchange, the Russian Defense Ministry said that Lieutenant General Valery Asapov was killed by shelling at a command post near Deir al-Zor where he was assisting Syrian government forces.
"The death of the Russian commander is the price, the bloody price for the two-faced American policy in Syria," Ryabkov was quoted by state-run RIA Novosti and other news agencies as saying.
"The American side declares that it is interested in the elimination of [IS]...but some of its actions show it is doing the opposite and that some political and geopolitical goals are more important for Washington," he said.
Nauert denied that and called the Russian accusations "untrue and unhelpful," but said the United States would continue de-confliction efforts aimed at avoiding deadly incidents.
"Claims that U.S. supports ISIS or complicit in Russian commander death has no basis in fact. U.S./Coalition has one objective: defeat of ISIS," the State Department spokeswoman said on Twitter, using another acronym for Islamic State.
The United States made similar accusations against Moscow last week, asserting that Russian forces say they are targeting IS fighters, but are in fact targeting U.S.-backed forces.
In the latest incident, the U.S.-allied SDF militia said Russian and Syrian forces appeared to be targeting its fighters because they recently captured the largest gas field in the region, Koniko, on September 23.
"Russian and regime forces have mounted a treacherous attack against our forces...with artillery and aircraft," the SDF said in a statement.
"We will not stand by with our arms crossed and we will use our legitimate right to self-defense," it said.
The Russian military denied the accusations, saying it conducts accurate air strikes on targets "confirmed by multiple sources."
Syrian government forces, backed by Russian air power and Iranian-allied militias, have gained control of most of Deir al-Zor on the western side of the Euphrates River.
Meanwhile, the U.S.-backed, Kurdish-led SDF militia has said that their campaign to capture the IS stronghold of Raqqa, north of Deir Al-Zor, is in its final stages.