U.S. airstrikes against Islamic militants in Iraq have begun -- a day after President Barack Obama authorized those strikes, and humanitarian aid in that country's north.
Federal aviation authorities are also prohibiting U.S. airlines and other commercial carriers from flying over Iraq, saying hostilities there could threaten safety.
A Pentagon spokesman says two F/A-18 jets dropped 500-pound bombs on a piece of artillery and the truck towing it.
The Pentagon says the militants were using the artillery to shell Kurdish forces defending the city of Irbil.
The planes took off from the aircraft carrier USS George HW Bush in the Persian Gulf.
The spokesman says it's not clear how many militants may have been killed in the strike.
In a speech last night in which he threatened to renew U.S. military involvement in Iraq, Obama also announced that U.S. military planes had already dropped food and water to tens of thousands of members of Iraqi religious minorities atop a mountain surrounded by militants.
Defense Secretary Chuck Hagel told reporters Friday that the U.S. military has enough intelligence resources and assets in place to launch strikes by both manned and unmanned aircraft in the region.
Iraqi and Kurdish officials are welcoming the U.S. decision to authorize airdrops of humanitarian aid and airstrikes in northern Iraq to counter advancing Sunni radical militants.
A string of victories across the north of the country by the radical group Islamic State and their allies have sent Iraq's minorities fleeing for their lives, exacerbating the country's already-dire humanitarian crisis with another 200,000 people displaced.
The FAA announced the ban against flights over Iraq Friday, citing the "potentially hazardous situation" created by fighting between militants and Iraqi security forces and their allies.
The ban applies to all U.S.-registered planes except those operated by foreign carriers and to FAA-licensed pilots. There is an exception for flights operated with U.S. government permission and for emergency situations.
The FAA previously had limited flights over Iraq to altitudes no lower than 30,000 feet.
The ban comes just three weeks after a Malaysia Airlines plane with nearly 300 people on board was shot down over eastern Ukraine.