The US-led coalition fighting the Islamic State (ISIS) group denied Monday its planes carried out air strikes that killed at least three Syrian regime troops a day earlier, even as Bashar al-Assad’s regime condemned the strikes.

“We’ve seen those Syrian reports but we did not conduct any strikes in that part of Deir Ezzor yesterday. So we see no evidence,” said Colonel Steve Warren, spokesman for the coalition.

He said the coalition’s only strikes in Deir Ezzor on Sunday were some 55 kilometers (34 miles) away from the area where the troops were allegedly killed.

“We struck 55 km away from the area that the Syrians say was struck. That was the only area in Deir Ezzor we struck yesterday,” he told AFP. “There were no human beings in the area that we struck yesterday, all we struck was a wellhead.”

Syria’s government on Monday strongly condemned what it said were US-led strikes that killed at least three Syrian soldiers at an army base.

The Syrian Observatory for Human Rights, a Britain-based monitor, also reported the strikes, saying four troops had been killed and 13 wounded.

“The Syrian Arab Republic strongly condemns this flagrant aggression by the US-led coalition forces, which blatantly violates the objectives of the UN charter,” the Syrian foreign ministry said in a letter to the UN Security Council and secretary general.

“The Syrian foreign ministry demands the UN Security Council act immediately in the face of this aggression and take appropriate measures to prevent its recurrence,” the letter added.

It said three Syrian soldiers had been killed and 13 wounded in strikes by four coalition planes on an army camp in the eastern province of Deir Ezzor.

The Britain-based Syrian Observatory for Human Rights monitor earlier said four Syrian soldiers had been killed and 13 injured.

The monitor said the strikes had hit a camp in the west of Deir Ezzor, around two kilometers (one mile) from an area controlled by the Islamic State (ISIS) group.

The Observatory said it was the first time a US-led coalition strike had killed Syrian government troops.

Much of Deir Ezzor province is under the control of ISIS, which is regularly targeted there by the US-led coalition, but the regime remains present in small areas, including in the provincial capital.

The coalition has been carrying out strikes against ISIS since September 2014, and does not coordinate with the government in Damascus.

The Syrian government has regularly criticized the US-led strikes as ineffective and illegal because they are not coordinated with regime forces, and the ministry that the Deir Ezzor incident was further evidence of the coalition’s failings.

“The US coalition lacks the seriousness and credibility to effectively combat terrorism,” the ministry said.

AFP contributed to this report.