We cannot 'corroborate' death of IS No. 2: US

The US Central Command has said that it cannot "corroborate" the death of the second-in-command of the Islamic State (IS) terrorist group, Abu Ala al Afri, in the Iraqi town of Tal Afar, Efe news agency reported.

"We are aware of media reports that the second-in-command of ISIL has been killed in a coalition airstrike in Tal Afar and have no information to corroborate these claims," CENTCOM said in a communique on Wednesday, referring to the IS by the US administration's preferred designation.

The statement was released after the Iraqi defense ministry on Wednesday announced the death of Al Afri and other IS leaders in an airstrike by the US-led international coalition.

In a statement, the defence ministry said that "according to precise information from the intelligence (services)", the coalition bombed the Al Shuhadae mosque in the Al Ayada neighborhood in Tal Afar, 60 km west of Mosul, where the IS number two was meeting with other members of the group.

The US Central Command, however, denied that the coalition had attacked a mosque.

"We can confirm that Coalition aircraft did not strike a mosque as some of the press reporting has alleged," the military command said.

"We have significant mitigation measures in place within the targeting process and during the conduct of operations to reduce the potential risks of collateral damage and civilian casualties," CENTCOM added.

A top Iraqi security official told Efe that Al Afri, whose real name is Abdulrahman Mustafa, joined Al Qaeda in Afghanistan in 1998 and participated in attacks in "other parts of the world" before returning to Iraq.

Al Afri was one of the main associates of the former leader of Al Qaeda in Iraq, Jordanian Abu Musab al Zarqawi, who was killed in a US airstrike on the city of Baquba in 2006.

The IS last summer took control of Mosul, Iraq's second largest city, as well as significant territory in the northern part of that country and neighbouring Syria, where it has proclaimed a caliphate.

Last year, the US began an aerial offensive against IS positions in the region.

Washington launched the airstrike campaign unilaterally in August 2014 limiting it to just Iraq, but later, with the creation of an international coalition, the campaign was expanded to Syria.