DAMASCUS/TEHRAN - The US military launched airstrikes targeting positions of pro-Iran militias in the eastern Syrian province of Deir al-Zour on Wednesday, killing six Syrian and foreign fighters, a war monitor reported.

The US strikes early Wednesday came after a drone attack on the US al-Tanf base in southeastern Syria on Aug 15.

After the strikes, the US forces were placed on alert and carried out live ammunition training at the al-Tanf bases and others in the eastern and northeastern regions, according to the Syrian Observatory for Human Rights.

The Iranian militias have yet to respond, but reports said their weapons have been aimed toward the US bases in Deir al-Zour.

Joe Buccino, spokesman of the US Central Command, said earlier in a statement that the precision airstrikes in Deir al-Zour were carried out "at US President (Joe) Biden's direction."

"The precision strikes are intended to defend and protect US forces from attacks like the ones on Aug 15 against US personnel by Iran-backed groups," he added.

However, the Iranian foreign ministry called the US strikes in Syria "a violation of safety and sovereignty of Syria," denying the targets of the US strikes are linked to Iran.

The Syrian government has yet to comment on the strikes.

Also on Wednesday, the Iranian Foreign Ministry spokesman condemned the US military's airstrikes on "people and infrastructure" in Syria's eastern province of Deir al-Zour, rejecting any link between Iran and the targeted groups.

Nasser Kanaani made the remarks in a statement on the ministry's website, saying the US military forces' continued presence on parts of Syrian soil is against international law, violates the Arab country's national sovereignty, and is considered as occupation.

He called on the US forces to immediately leave Syria and end their plunder of the country's oil and grain resources.