The Middle East has seen a surge in attacks on US forces, which Washington blames on Tehran-aligned armed groups across the region, since the start of the Israel-Hamas war on October 7.

The Syrian Observatory for Human Rights said "10 pro-Iranian fighters, including three Syrians, were killed and more than 30 were wounded" in at least nine air strikes that were "likely American".

They targeted military positions in Albu Kamal and its surroundings, in Deir Ezzor province near the border with Iraq, added the Britain-based Observatory, which has a broad network of sources inside war-torn Syria.

It said a weapons shipment from Iraq and an ammunition warehouse were also hit.

Meanwhile Lebanon's powerful Hezbollah movement, which like Hamas in the Gaza Strip is supported by Iran, announced on Saturday the death of four of its fighters "on the road to Jerusalem" -- a reference to militants killed in hostilities since October 7.

It was unclear whether they had died in the strikes in the Albu Kamal area.

The latest violence came amid an increase in attacks against US and anti-jihadist coalition forces in Syria and Iraq since the start of the Israel-Hamas war. There has also been regular cross-border fire between Israel and Hezbollah in south Lebanon.

The US launced air strikes in Iraq this week after a drone attack in the Kurdistan region wounded three US military personnel, one critically.

In mid-November, at least eight members of Tehran-linked groups were killed in US strikes that hit two sites in Deir Ezzor province, according to the Observatory.

Washington has counted more than 100 attacks launched against US targets in Syria and Iraq since mid-October, according to a military official speaking on condition of anonymity.

The majority have been claimed by the Islamic Resistance in Iraq, a loose formation of Iran-linked armed groups which oppose US support for Israel.

The United States has around 2,500 troops in Iraq and 900 in Syria as part of a multinational coalition fighting the Islamic State group.