NAIROBI (Reuters) - Four people were killed and 11 injured when their landcruiser detonated a bomb planted on a road in northeast Kenya on Friday, a senior government official said, in the latest of a series of such attacks.

Last month, at least eight police officers were killed in two roadside bombings in the area, with al Shabaab Islamist militants based in neighboring Somalia claiming responsibility.

Early on Friday a public service vehicle was blown up by an improvised explosive device (IED) between Fino and Sheikh Barow, Mandera County Commissioner Frederick Shisia said.

“A (Toyota) Landcruiser which was carrying about 15 people ran over an IED. It exploded, killing four instantly, and injured 11,” he told Reuters by phone.

Among the casualties were two local leaders. “One chief died and another got seriously injured,” Shisia said.

“We suspect it is al Shabaab militants, as they are the ones who are behind planting of IEDs in the area.”

Al Shabaab, fighting to overthrow Somalia’s government and impose its own harsh interpretation of sharia law, says it will continue to attack Kenya until it withdraws its troops from an African Union peacekeeping mission in Somalia.