The United States on Friday denied threatening the family of executed reporter James Foley with prosecution had they raised a ransom for his release, insisting the government did everything possible to bring him home.

Foreign Minister Jebran Bassil is scheduled to travel to Jeddah to attend talks on joint action against the Islamic State (IS) group, a cabinet minister said.

The minister, who was not identified, told al-Liwaa newspaper published Wednesday that Bassil will attend a meeting between U.S. Secretary of State John Kerry and around nine Arab states in addition to Turkey.

President Barack Obama vowed Wednesday that the United States would not be intimidated by the beheading of a second American reporter but acknowledged the fight against the jihadists would take time.

Obama pledged that justice would be done to the Islamic State (IS) killers of 31-year-old reporter Steven Sotloff, wherever they hid and however long it took.

The Pentagon violated U.S. law when it controversially swapped a soldier held in captivity for five years in Afghanistan for five Taliban detainees without giving lawmakers sufficient notice, congressional investigators found Thursday.

The Pentagon used $988,400 of its wartime funding for the transfer that freed Sergeant Bowe Bergdahl.

The White House urged Moscow on Friday to stop its "extremely dangerous and provocative" attempts to destabilize Ukraine, where tensions have soared again in the past 24 hours.

The United States warned Thursday a jihadist offensive in northern Iraq could provoke a "humanitarian catastrophe," amid reports that President Barack Obama was considering U.S. military action.

"It is a situation that we are looking at very closely," White House spokesman Josh Earnest said, following reports that Obama was talking with military advisers about options for intervention.

Amid the escalating death toll in Gaza, U.S. officials finally sharpened their tone Wednesday condemning an attack on a U.N. school as patience with "crazy" Israeli criticism of would-be-peacemaker John Kerry snapped.

A top-ranking North Korean military official has threatened a nuclear strike on the White House and Pentagon after accusing Washington of raising military tensions on the Korean peninsula.

The threat came from Hwang Pyong-So, director of the military's General Political Bureau, during a speech to a large military rally in Pyongyang Sunday on the anniversary of the armistice that ended the 1950-53 Korean War.

President Barack Obama has not decided how to respond to rampant Sunni militants grabbing swathes of Iraq, but is looking at every option short of sending U.S. combat soldiers back to war.

Officials said Wednesday that Obama had not ruled out any possible courses of action, including air strikes against Islamic State of Iraq and the Levant (ISIL) fighters.

About 275 U.S. military personnel are being deployed to Iraq to help American personnel and protect the embassy in Baghdad, President Barack Obama said Monday in a letter to Congressional leaders.

The force, which began deploying on Sunday, has been sent "for the purpose of protecting U.S. citizens and property, if necessary, and is equipped for combat," Obama wrote.