Syrian state media said on Monday that U.S.-led coalition aircraft had bombed an army position in eastern Syria, causing dozens of deaths and injuries, but the U.S. military denied responsibility.
Syrian state media reported an airstrike against pro-government forces in the far east of the country, while Iraqi officials said 20 Shiite paramilitaries were killed just across the border.
A commander in the military alliance backing Syrian President Bashar Assad told Reuters that drones, "probably American," had bombed positions of Iraqi factions between the border towns of Al-Bukamal and Al-Tanf and Syrian military positions.
The Syrian Observatory for Human Rights watchdog group said at least 40 members of pro-Iranian militias, including Hezbollah, were killed in the attack.
Syrian state TV reported that the airstrike occurred around midnight in the village of al-Hari, to the southeast of Al-Bukamal, and was carried out by the U.S.-led coalition battling the Islamic State group.
But a coalition spokesman said it had not carried out any strikes in the area.
The state TV report, quoting an unnamed military official, gave no breakdown of the casualties other than saying there "were several martyrs and others were wounded."
In Baghdad, Iraqi officials said Popular Mobilization Forces – the mostly Shiite state-sanctioned paramilitaries – came under attack south of the town of Qaim, just across the border from Al-Bukamal. They said 20 fighters were killed and dozens were wounded, adding that the cause of the attack was not immediately clear. The Iraqi officials spoke on condition of anonymity because they were not authorized to speak to the media.
U.S. military spokesman Col. Sean Ryan said the coalition was looking into the reports.
"We are aware of the strike near Bukamal; however, there have been no strikes by U.S. or coalition forces in that area," he said. "We're looking into who that could possibly be, but it wasn't the U.S. or the coalition."
Syrian and Iraqi forces have driven ISIS from virtually all the territory it once held in both countries, but the group still controls some remote areas along the border.
Syrian troops and allied militias, backed by Russian airstrikes, have been conducting operations west of the Euphrates River, while the U.S.-backed Syrian Democratic Forces, a Kurdish-led militia, is operating on the eastern banks. The U.S.-led coalition has struck pro-government forces in the past when they have tried to cross the river. The overnight attacks took place on the western side.
Last week, Assad said he regarded the United States as an occupying power in Syria and that the position of his state was to "support any act of resistance, whether against terrorists or against occupying forces, regardless of their nationality."
On Thursday, Washington said it would take "firm and appropriate measures" in response to Syrian government violations in a so-called de-escalation zone in the southwest of the country.
The southwest of Syria, bordering Jordan and the Israeli Golan Heights, is one of the remaining parts of the country still outside the control of the state after seven years of conflict.
