US shipping arms to Iraqi Kurds: State Department

The United States has begun urgently shipping arms and ammunition to the Iraqi Kurdish forces battling an advance by extremist Islamic State militants, a State Department spokeswoman said Monday.

"We're working with the government of Iraq to increasingly and very quickly get urgently needed arms to the Kurds," Marie Harf told CNN.

Security sources said Monday that IS fighters had defeated Kurdish troops in the flashpoint Iraqi town of Jalawla, killing at least 10 in a fierce two-day battle.

Kurdish forces rescued more than 10,000 Iraqi Yazidis from Mount Sinjar in northern Iraq where they have been trapped for the past week over the weekend. 

France and Britain have pledged support for a US-led operation helping Iraqi civilians - many of them from the Yazidi minority - who are fleeing a murderous advance by IS militants.

While all three Western countries are providing emergency aid for the besieged civilians, the United States has also been conducting air strikes on IS positions.

Earlier Monday, Prime Minister Nuri al-Maliki said he would sue the country's president, Kurdish veteran Fuad Masum on Monday, saying he had violated the constitution twice, essentially by failing to designate Maliki as the prime minister.

"Today I will file a formal complaint to the federal court against the president," Maliki said in an address broadcast on the stroke of midnight on state television.

Kerry responded, throwing his weight behind Iraq's newly-elected Masum to help fight the militants and warned Maliki not to stir up trouble. 

Many Iraqis see Maliki as partly responsible for the recent conflict in northern Iraq, saying he has institutionalised sectarianism.