A bomb attack in Yemen is reported to have killed three policemen and wounded four civilians, reports AP.

The bomb exploded as they were parking their car in the city of Maareb, about 170 km east of the Yemeni capital, Sanaa.

Witnesses said the vehicle was totally destroyed by the blast.

The bombing follows a series of similar attacks in recent weeks, aimed at government, foreign diplomatic and commercial targets.

Foreign tourists come under regular attack in Yemen - attacks often claimed by al-Qaeda.