Coast Regional Police Commander Noah Mwivanda confirmed the incident in Milihoi area, which paralyzed transport in the region.

There were six police officers in the vehicle, he said.

Mwivanda said Somali militants ambushed the police officers who were returning to their camp in Mpeketoni after regular patrols in al-Shabab-prone areas.

He said the ambush prompted a fierce gunfight with insurgents, who later vanished into the forest.

"Our officers have been injured and might need referrals,” he told Xinhua by phone.

The police commander said two officers have been hospitalized while the search for the other three is ongoing.

A Kenya Red Cross official who requested anonymity said that the attack has paralyzed operations along Garsen-Lamu Road.

All public service vehicles from Mombasa to Lamu are stuck at Mkunubi area while commuter buses from Lamu have been barred from leaving.

Hundreds of passengers were stranded on the road as security forces engage the militants in heavy shootout.

Al-Shabab militants have changed tactics and resorted to using improvised explosive devices to carry out attacks in parts of the coastal and northeastern regions, according to police.

The militant group is believed to have fighters operating in the area’s Boni forest that has poor communication network and terrains, slowing down police operations.