Yemeni officials say two security officials were assassinated in separate incidents by unknown assailants.

The officials say that Police Chief Adel al-Asshabi of Bayda province was killed by a bomb planted in his vehicle on Sunday. Mohammed al-Dhali, of the special forces, was gunned down by attackers on a motorcycle in the rebel-held capital, Sanaa.

They spoke on condition of anonymity because they were not authorized to speak to the press. No group has claimed responsibility for the killings.

Yemen has been mired in a conflict pitting the Shiite Houthi rebels against the internationally-backed government, which is allied with a Saudi-led coalition. The armed forces have splintered, with some allying with the rebels and others remaining loyal to the government.