(Adds background, governor quotes)
SANAA, April 16 (Reuters) - Three policemen were killed and four civilians injured early on Wednesday in an explosion targeting a police vehicle in a volatile province in Yemen, local officials said.
The attackers placed a bomb on the ground where a police patrol parks every day, Aref al-Zoka, the governor of Marib province said without giving more details.
“An investigation is under way and the suspects are being pursued,” he added, without saying who the suspects were.
The blast follows a series of attacks, including one on Canadian oil company Nexen, in the Yemeni capital Sanaa last week.
Yemen, the ancestral home of al Qaeda leader Osama bin Laden, has jailed dozens of Islamic militants for involvement in bombings of Western targets and clashes with authorities.
The oil-producing country joined U.S.-led efforts to fight terrorism after the Sept. 11 attacks on U.S. cities in 2001 and has itself experienced attacks on foreign tourists, oil installations, and U.S. and French ships.
One of the poorest countries outside of Africa, Yemen has also had a wave of riots in the south in which dozens of police and demonstrators were injured. (Reporting by Mohammed Sudam; Writing by Ola Galal; Edited by Alison Williams)