UPDATE1-Yemen says Shi'ite rebels kill officer, bodyguards

(Updates with ambush, killing of officer, bodyguards)

SANAA, July 21 (Reuters) - Suspected Shi'ite rebels killed an army colonel and two of his bodyguards in north Yemen on Sunday, a local official said.

Yemen, one of the poorest Arab countries, has been battling a wave of al Qaeda attacks, as well as Shi'ite rebellion in its north and secessionist sentiment in the south. The violence has raised Western fears that Yemen could become a new haven for Islamist militants.

"Houthi supporters are suspected to have carried out the attack," the official from Saada province, who declined to be identified, told Reuters in the capital Sanaa by telephone.

The officer was part of the army staff in the northern province of Saada, the site of a rebellion by Shi'ite Muslims led by rebel leader Abdul-Malik al-Houthi.

In neighbouring al-Jouf province, 10 people were killed in sectarian clashes on Saturday and Sunday over the control of a mosque between the Shi'ite rebels and followers of the opposition Sunni Islamist al-Islah party.

Neighbouring Saudi Arabia, the world's largest oil exporter, has said it fears instability in Yemen could allow it to become a launch pad for a revival of a 2003-2006 campaign by al Qaeda militants to destabilise the U.S.-allied ruling Al Saud family.

Reporting by Mohamed Sudam and Mohammed al-Ghobari; writing by Firouz Sedarat; editing by Ralph Boulton