Abu Ayyub al-Masri, also known as Abu Hamza al-Muhajir, is thought to be the leader of Al Qaeda in Iraq.

On May 8, 2008 Iraqi forces arrested a man thought to be al-Masri in Mosul, northern Iraq. Mosul is regarded as one of the Al Qaeda's last major hold-outs in the country. Reports later said it was a man with a similar name.

Al-Masri took over control of Al-Qaeda in Iraq after his predecessor, Abu Musab al-Zarqawi, was killed in a US air strike June 2006.

He is thought to have met al-Zarqawi at an Al Qaeda training camp in Afghanistan in 2001 then going on to help Zarqawi create the first al-Qaeda cell in Baghdad.

In April 2007, he was named "minister of war" in the 10 man Islamic State of Iraq cabinet, a collective of Sunni Islam organizations of militant groups.

The combined US Iraqi forces have been fighting for control of Mosul for months leading up to al-Masri's arrest. Sunni extremists moved there after they turned against their former Al Qaeda allies - the Sunni Awakening.