US military bases in eastern Syria were "attacked with multiple casualties", leading to an exchange of shelling, according to reports.
In return, a US aircraft reportedly targeted the positions of the Iranian-backed forces in Al Salihiya, Al Bukamal and Al Joura, local media are reporting.
Iran-backed militants reportedly targeted another base hosting American forces in Syria's Conoco gas field with at least eight rockets on Friday evening.
In response, the US has bombed the positions of these militant groups in Syria’s Deir Ez-Zor.
An American official confirmed that there was at least one casualty in the missile attack on a US military base, according to Al Jazeera correspondent, Fadi Mansour.
Syria-based journalist Mohammad Hasan reported that Iranian militias and militias affiliated with the Syrian regime's army bombarded with Grad missiles and 107 caliber missiles.
Syrian news outlet Naher Media reported that the Iranian militias are on alert and evacuating their headquarters, amidst the flight of drones over the area.
It comes as President Joe Biden said on Friday that the US would respond “forcefully” to protect its personnel, after its forces retaliated with airstrikes on sites in Syria used by groups affiliated with Iran’s Revolutionary Guard.
A suspected Iranian-made drone had attacked the US base on Thursday, which killed a US contractor and wounded six other Americans in northeast Syria.
“The United States does not, does not seek conflict with Iran,” Biden said in Ottawa, Canada, where he is on a state visit.
But he said Iran and its proxies should be prepared for the US “to act forcefully to protect our people. That’s exactly what happened last night.” Activists said the US bombing killed at least four people.
While it’s not the first time the US and Iran have traded strikes in Syria, the attack and the US response threaten to upend recent efforts to deescalate tensions across the wider Middle East, whose rival powers have made steps toward détente in recent days after years of turmoil.
According to US officials, two simultaneous attacks were launched at US forces in Syria Friday.
Officials said that based on preliminary information, there was a rocket attack at the Conoco plant, and one US service member was injured but is in stable condition.
At about the same time, several drones were launched at Green Village, where US troops are also based.
One official said that all but one of the drones were shot down, and there were no US injuries there.
On Friday night, two Syrian opposition activist groups reported a new wave of airstrikes on eastern Syria that hit positions of Iran-backed militias after rockets were fired at a Conoco gas plant that has a base housing American troops.
Several US officials denied that the US launched any attacks late Friday.
