Shafaq News/"You can't act with impunity. Be careful," President Biden told reporters in Texas when asked what message he was sending Iran with the strikes.

US air strikes targeted Iranian-backed factions in the east of the country on Thursday after Iran’s missile attacks on US targets in Iraq.

The air strikes targeted faction sites on the Syrian side of the Iraqi-Syrian frontier, where groups backed by Iran control an important crossing for weapons, personnel and goods. Local sources and a medical source in eastern Syria told Reuters that at least 17 people had been killed, but gave no further details. That toll could not be confirmed.

The Pentagon said it had preliminary information about casualties, but did not provide any further details.

Western officials and some Iraqi officials accuse Iranian-backed groups of involvement in deadly rocket attacks on US sites and personnel in Iraq over the last month.

White House spokeswoman Jen Psaki said the air strikes in Syria were meant to send the message that Biden will always act to protect Americans.

Future US actions in the region will be deliberative and will aim to deescalate tensions in Syria, Psaki said.

It was not clear how, or whether, the US strikes might affect efforts to coax Iran back into negotiations about both sides resuming compliance with the 2015 nuclear deal.