Mr Maliki said on national TV that the Iraqi al-Qaeda leader Abu Ayyub al-Masri and Abu Omar al-Baghdadi, who led an affiliate group, were dead.

US Vice-President Joe Biden said their deaths were "potentially devastating blows" to al-Qaeda in Iraq.

Mr Maliki said both had been killed in Salaheddin province, west of Baghdad.

Iraqi TV showed pictures of both men before and after their deaths.

The attack was carried out by ground forces which surrounded the house, and also through the use of missiles," Mr Maliki said.

Speaking in Washington, Mr Biden said the operation "demonstrates the improved security, strength and capacity of Iraqi security forces".

In a statement, the commander of US forces in Iraq, Gen Raymond Odierno, said: "The death of these terrorists is potentially the most significant blow to al-Qaeda in Iraq since the beginning of the insurgency."