WASHINGTON (AP) — Declaring that "America is coming to help," President Barack Obama is authorizing U.S. airstrikes if necessary and airdrops of humanitarian aid in northern Iraq.

Both missions seek to counter advancing Islamic militants and the threat they pose to Americans as well as Iraqi civilians.

The threat to renew U.S. military involvement in Iraq's long sectarian war came in a televised speech by Obama late Thursday night.

The president says American military planes already have carried out airdrops of food and water to tens of thousands of Iraqi religious minorities atop a mountain surrounded by militants.

The announcements reflect the deepest American engagement in Iraq since U.S. troops withdrew in late 2011 after nearly a decade of war.

(Story by: Julie Pace and Robert Burns, The Associated Press)