[Several updates] IF THIS is confirmed, it's big stuff; these two guys were really senior terrorists:

Iraqi Prime Minister Nouri al-Maliki announced Monday that the two leaders of the Sunni insurgent group al-Qaeda in Iraq have been killed.

In a televised news conference, Maliki said Abu Ayyub al-Masri, the leader of al-Qaeda in Iraq, and Abu Omar al-Baghdadi, the head of the Islamic State of Iraq, an umbrella group that includes al Qaeda in Iraq, were killed in a recent raid.

Their death or capture has been announced before, so we'll have to wait for more corroboration, though.

UPDATE. CNN says Maliki showed reporters photos of the two men (depicting them dead, I assume).

UPDATE II. Reuters:

Maliki said Masri, also known as Abu Hamza al-Muhajir and thought to be an Egyptian, and Baghdadi were killed in Thar-Thar, a rural area 80 km (50 miles) west of Baghdad that is regarded as a hotbed of al Qaeda activity. The operation took place over the last couple of days.

"The attack was carried out by ground forces, which surrounded the house, and also through the use of missiles," Maliki told a news conference. "U.S. forces also participated."

He said the house was destroyed and the two bodies were found in a hole in the ground inside in which they had been hiding.

The news agency also notes that there's no confirmation yet from the US military.

UPDATE III. According to the BBC, the US military has indeed confirmed that the two guys have been killed by Iraqi forces.

UPDATE IV. Totally confirmed by the US, AP reports:

U.S. forces commander Gen. Raymond Odierno says the deaths are potentially the most significant blow to the terrorist organization since the beginning of the insurgency.

The U.S. military said they were killed in a nighttime raid on their safehouse Sunday near Tikrit, the hometown of former Iraqi dictator Saddam Hussein.

UPDATE V. From the horse's mouth.