Congressman Seth Moulton says the US response to the attack on its Tower 22 base in Jordan must send “a clear, decisive message” to both the militia groups in the region and their backers.

Speaking to BBC News, the Democrat lawmaker says the response must also be “politically calculated to ensure that the message of deterrence gets through”, particularly to Iran.

“We don’t want to empower the warmakers in Iran. That would be playing into our enemy’s hands,” he says.

The Islamic Resistance in Iraq, an umbrella group for Iran-backed militia, claimed responsibility for the attack, which left three dead.

Iran denies involvement in the attack, calling accusations to the contrary “baseless”.