Shafaq News/ The United States sent an "unambiguous message" with an airstrike against Iranian-backed factions in eastern Syria, the White House said Friday.

President Joe Biden is "sending an unambiguous message that he's going to act to protect Americans and when threats are posed he has the right to take an action at the time and the manner of his choosing," Press Secretary Jen Psaki said.

Psaki said the decision behind the strike was "deliberative" and that Biden's aim was for "deescalating activity in both Syria and Iraq."

Psaki, the White House spokeswoman, said the Pentagon briefed congressional leadership "before the action."

"There will be a full classified briefing early next week at the latest," she said.

The Pentagon said Thursday's strike, which according to a Syrian war monitoring group killed 22 militia members, was in response to a series of rocket attacks targeting US soldiers in Iraq.