Washington (AFP) - President Barack Obama is considering ordering US air strikes against Sunni extremists in northern Iraq and humanitarian food drops to beleaguered civilians, reports said Thursday.

US media, citing senior White House officials, said Obama was weighing military options after jihadists from the so-called "Islamic State" attacked Christian and Yazidi minority communities.

“There could be a humanitarian catastrophe there,” an official told the New York Times, warning that a decision on military action was expected “imminently — this could be a fast-moving train.”

Obama came to office determined to end US military involvement in Iraq and in his first term oversaw the withdrawal of the huge ground force deployed there since the 2003 American invasion.

But recent rapid gains by the Islamic State, a successor group to Al-Qaeda's former Iraqi and Syrian operations, compelled him to send military advisors back to Baghdad evaluate the situation.

The United Nations Security Council was to hold emergency talks on the crisis later Thursday, and France has pledged support for forces "engaged in battle" against the IS radicals.

The group, along with allied Sunni factions, is at war with Iraqi Prime Minister Nuri al-Maliki's mainly Shiite government forces and with the peshmerga forces of the Kurdish autonomous region of the country.

In late June it proclaimed a "caliphate" straddling rebel-held areas of Syria and Iraq and seized the major city of Mosul. In recent days it has seized towns formerly populated by Christians and Yazidis.

Iraqi religious leaders say Islamic State militants have forced 100,000 Christians to flee and have occupied churches, removing crosses and destroying manuscripts.

Meanwhile, several thousand Yazidis, members of an ancient pre-Muslim religious minority, are stranded on high ground after being driven out of their home town of Sinjar by IS fighters.

US press reports said that Obama could decide to mount a humanitarian operation to save displaced or besieged civilians, or launch military strikes to halt the IS advance.

There was no immediate comment from the White House.