One of the leaders of the top US foe in Iraq, Abu Musab al-Zarqawi, was arrested in the northern city of Mosul, national security adviser Qassem Daoud said. "We arrested a few days ago Abu Said, one of the leaders of the Zarqawi network in the city of Mosul," Daoud told reporters. He did not elaborate on the identity of the rebel leader and his rank in Zarqawi's Al-Qaeda linked organisation, but said information which led to the arrest came partly from local residents. Zarqawi has a 25-million-dollar bounty on his head and his organisation -- which has claimed responsibility for a string of deadly bombings and kidnappings -- was said to be headquartered in Fallujah before US and Iraqi forces launched a massive offensive against the city on November 8. US military officials fear that many Fallujah rebels may have fled the Sunni city before the onslaught and are regrouping elsewhere. According to a government report published in December, Mosul was home to the second largest concentration of Zarqawi operatives in Iraq, with a contingent of close to 400. US troops backed by Iraqi commandos are currently involved in a vast operation to root out the insurgency in Mosul, the country's third largest city.