A commander in a pro-government alliance meanwhile told Reuters news agency that several Iraqi militiamen had been killed in strikes by drones, "probably American", on positions between Albu Kamal and al-Tanf - an area 230km (145 miles) to the south-west where some U.S. military personnel are based.
"US planes fired two guided missiles at a fixed position of Hashed al-Shaabi units on the border with Syria, killing 22 fighters and wounding 12", the Iran-backed Hashed said, locating the raid at "700 metres (yards) inside Syria".
According to the Syrian military officials, Imam Ali Brigades and Righteous Brigades members were killed in the military action, which took place south of Al-Bukamal, about 150 kilometers east of Deir Ezzor.
FILE PHOTO: A man sits near a poster of Syrian President Bashar al-Assad during the re-opening of the road between Homs and Hama in Talbisi, Syria June 6, 2018.
The Syrian Observatory for Human Rights said earlier that almost 40 foreign fighters allied to Syria's regime were killed in the raid in eastern Syria.
The UK-based Observatory said the strikes had killed 52 people.
The Syrian government has repeatedly denounced the attacks of the Western Coalition forces, led by the United States, against the civilian population and positions of the army, which killed hundreds of residents and soldiers. Reuters could not independently verify the Observatory's report of casualties.
Throughout Syria's seven-year war, Israeli officials have disclosed scores of air strikes within the neighbouring country against suspected arms transfers to Hezbollah or Iranian deployments.
"I'm sure you are familiar with the Israeli policy of not commenting on foreign reports, so I will stick to that policy and I can not comment on any reports in foreign media", said Israeli Lt. Col. Jonathan Conricus.
Israel, alarmed about the clout of arch enemies Iran and Hezbollah, has been pressing Russia, Assad's other key ally, to make sure they do not entrench their military sway in Syria.
Regime forces control land west of the Euphrates River that runs through the province, while the SDF are battling to expel IS from a string of villages on the river's eastern banks near the Iraqi border.
Prime Minister Benjamin Netanyahu told his cabinet he had "repeated and clarified" his Syria policy in weekend phone calls with Russian President Vladimir Putin and U.S. Secretary of State Mike Pompeo.
Damascus says it considers the United States an occupying force in Syria and supports any resistance against U.S. forces.