A US military base in Syria on Monday was targeted by missiles fired from areas under the control of Syrian army and some militia, and US war planes after the attack carried out strikes against militia posts, according to a report by Syrian Observatory for Human Rights (SOHR).

The US base in Conoco gas field were targeted with four missiles, SOHR said, noting that the attack took place when a convoy of military reinforcement was about to reach the base. It added that the missile strikes forced the convoy to stop before it could enter the base.

No casualties have been reported after the attack.

The missile attack was followed by US air strikes on posts of the militia in the villages of Tabyah Shamiyah and Marrat in Deir Ezzor countryside, destroying rocket launchpads.

Rudaw cited the militia group "Islamic Resistance in Iraq" saying on its Telegram channel that it carried out a rocket attack against the Conoco oil field which is protected by the US troops and the Kurdish-led Syrian Democratic Forces (SDF).

Pentagon on Saturday put the number of attacks recently carried out against US bases in Iraq and Syria at 20.

At least 21 US personnel received minor injuries in attacks on Ain al-Asad air base and al-Tanf garrison on October 17 and 18, but all returned to duty, Pentagon said.