The US military says one of its bases in eastern Syria was targeted by a rocket attack on Monday.

In a statement, the military announced a rocket hit the Mission Support Site Conoco, the US oil company in eastern Syria, and another rocket was found at the attack point of origin, but they did not cause any casualties or damage.

No group has yet claimed responsibility for the attack. However, The Britain-based Syrian Observatory for Human Rights that monitors human rights in Syria suggested Iranian-backed militias may have been behind the attack.

The US forces targeted the positions of groups related to the Islamic Revolutionary Guard Corps in Syria with retaliatory airstrikes in late March.

The operation was a response to a suspected Iran-linked drone attack that killed a US contractor and wounded six other Americans in northeastern Syria.

Estimates show that currently, at least 900 US forces are present in Syria.

In late March, top US defense chiefs faced criticism from the Senate Armed Forces Committee claiming the response to Iranian attacks on US forces is weak and lacks deterrence.

Of 83 attacks in Iraq and Syria since President Joe Biden took office, just four retaliations have taken place.

The weak US approach to Iran has been a thorn in Biden’s side as the Democrats try to keep channels open with Tehran in the hope of reviving the nuclear deal, the JCPOA.