In response to an e-mailed query, the U.S. military said that "according to a senior US military official, Abu Ayyub al-Masri (also known as Abu Hamza al-Muhajir) has not been detained."

Late on Thursday, Iraqi Interior Ministry spokesman Maj. Gen. Abdul-Karim Khalaf told the state television that al-Muhajir was arrested during a police raid in the city of Mosul, 400 km north of Baghdad.

"The man confessed that he is Abu Hamza. A ministry photo of him was compared to his facial features," Maj. General Abdul-Kareem Khalaf told local news agency Voices of Iraq (VOI) on Friday.

According to VOI, the Iraqi government argued that the arrested was not al-Muhajir, though a spokesman for the Iraqi Defense Ministry, Ninewa governor and security sources confirmed the detention of the al-Qaida leader.

Ali al-Dabbagh, official spokesman for the Iraqi government, said "during a late hour on Thursday night, a person who belongs to al-Qaida network was arrested, but he was not Abu Hamza al-Muhajir."

Abu Hamza al-Muhajir was announced leader of al-Qaida in Iraq after its former chief Abu Musab al-Zarqawi was killed in a U.S. airstrike in 2006.

The U.S. military since then identified him as one of the prime candidates to assume direction of the Iraqi insurgency. The U.S. military had put a 5-million-U.S. dollar bounty for top Qaida leader in Iraq.