The United States has launched fresh strikes on Iran after Tehran targeted US bases in Jordan, ending a week-long lull and raising fears of a wider Middle East conflict involving Iraq, Saudi Arabia and Hezbollah.

The United States military launched "powerful" strikes on Iran on Thursday, in retaliation for Tehran's attacks targeting US bases in Jordan as the Middle East war reignited and again drew in the Islamic republic's proxies.

The first strikes after a nearly week-long lull in fighting dashed hopes of a return to negotiations.

"The strikes are a powerful response to yesterday's attempted Iranian attacks on US forces based in the Middle East", US Central Command said.

Saudi Arabia and the United States also announced strikes Wednesday on militant bases in Iraq, while US ally Israel accused Iran-backed Hezbollah of a truce violation.