The US military has killed four “enemy fighters” over the past 24 hours and destroyed rocket launchers used by Iran-backed militants in Syria, Central Command said on Thursday.
“Over the past 24 hours, in response to yesterday’s rocket attacks on Mission Support Site Conoco and Mission Support Site Green Village in north-east Syria, Centcom forces struck at Iran-affiliated militants in the area with AH-64 Apache attack helicopters, AC-130 gunships and M777 artillery, resulting in four enemy fighters killed and seven enemy rocket launchers destroyed,” US Central Command reported.
Centcom's announcement indicates a continued spate of proxy fighting in Syria.
Rockets landed in its Conoco and Green Village sites in north-east Syria, which led to a US response by attack helicopters. That exchange of fire between American troops and Iranian-backed fighters followed US air strikes on “Iran-linked” targets in the country.
Centcom believes up to three militants were killed in its response to the week's previous rocket attacks, a number that the Syrian Observatory for Human Rights has also reported.
In total, the watch group said casualties for Iranian-backed groups in the last day had escalated to nine by Thursday evening.
US President Joe Biden issued a letter to Congress on Thursday confirming he had ordered the August 23 strikes in Syria “to protect and defend the safety of our personnel, to degrade and disrupt the ongoing series of attacks against the United States and our partners, and to deter the Islamic Republic of Iran and Iran-backed militia groups from conducting or supporting further attacks on United States personnel and facilities”.
“The United States stands ready to take further action, as necessary and appropriate, to address further threats or attacks,” Mr Biden said.
Democratic congressional leaders in Washington praised the retaliatory strike, giving credit to President Joe Biden, and calling it a counter-terrorism operation.
“By ordering this self-defence operation, President Biden acted to protect American troops and the American people,” Adam Smith, chairman of the House Armed Services Committee, said in a statement.
“These strikes demonstrate that the United States can and will meet counter-terrorism challenges around the world and that professionals across our national security institutions will do what is necessary, proportionate and precise to protect US military personnel serving in dangerous circumstances while preventing harm to civilians and avoiding unnecessary escalation.”
Meanwhile, Republicans in Washington said the administration's position in continuing nuclear deal negotiations could be emboldening Iran's stance outside its borders.
“These attacks by Iran’s proxies against US service members show why we cannot cut a bad nuclear deal with Iran,” said Michael McCaul, the Republican leader on the House Foreign Affairs Committee.
“The Biden administration must walk away from this bad deal that will fuel Iran’s terrorist attacks on US soldiers and citizens.”
Iran said on Wednesday that it had received a response from the US about the EU's final draft for the revival of the 2015 nuclear deal with major powers. American officials also announced a potential breakthrough this week in the 16-month negotiations, saying Iran had dropped demands to block some UN inspections of its nuclear facilities.
But the latest attacks has escalated the tense situation in Syria, where 900 American troops are stationed primarily in the east of the country. It has also fuelled anti-Iran deal sentiments for many of the Biden administration's sceptics in Washington.
Former US president Barack Obama's administration sent forces to the country, joining forces to support the Kurdish-led Syrian Democratic Forces operations in their campaign against ISIS.
US troops in both Iraq and Syria are on “high alert” for further attacks by Iran-backed groups, a senior US commander said on Thursday.
Meanwhile, Iranian-backed militia forces were also on alert and repositioned in Al Mayadeen, Al Bokamal, Al Quriyah and the western banks of the Euphrates river, the UK-based human rights observatory reported.
The defeat of ISIS in certain regions in Syria allowed Iran-backed militias to establish a foothold there while fighting in support of President Bashar Al Assad during the brutal civil war that began in 2011.
The defeat of ISIS in Deir Ezzor, for example, allowed Iran's Islamic Revolutionary Guard Corps to assert its presence within Syria while Iraqi groups contributed to the strengthening of Iranian influence along the Syrian-Iraqi border, according to Washington think tank the Centre for Strategic and International Studies.