DUBAI, May 1 (Reuters) - A Kuwaiti man released from the U.S. prison in Guantanamo Bay in 2005 has carried out a suicide bombing in Iraq, his cousin told Al Arabiya television on Thursday.

A friend of Abdullah Saleh al-Ajmi in Iraq informed his family that Abdullah carried out the attack in Mosul, his cousin Salem told the Dubai-based television channel.

"We were shocked by the painful news we received this afternoon ... through a call from one of the friend's of martyr Abdullah in Iraq," said Salem al-Ajmi in a telephone interview aired by Arabiya.

He did not say when the suicide bombing happened.

Abdullah had been missing for two weeks and his family learned he left Kuwait illegally for Syria, he said. Abdullah had sent messages to his wife from Iraq.

Abdullah, 30, had a son after he was released from the U.S. naval base at Guantanamo Bay, Cuba, where the United States holds suspected terrorists, Salem said.

There were no indications Abdullah had any plans to join insurgents in Iraq although he became less sociable in the period before he disappeared, he said.

Many of the men held at Guantanamo were captured in Afghanistan in the U.S.-led war to oust the Taliban after the Sept. 11, 2001, attacks. Many have been held for years and nearly all are being held without charge.

Washington has designated Guantanamo prisoners "enemy combatants". (Reporting by Inal Ersan; Editing by Robert Woodward)