The Somali militant group al Shabaab said on Sunday its fighters had killed eight Kenyans, including policemen, in a cross-border raid and had taken two captives back into Somalia.
A Kenyan official confirmed two policemen had been killed and two were missing but could not confirm if they were kidnapped during the attack on Saturday night.
"We have gone 35 km into Kenya and burnt their base, Damajale, last night," Sheikh Abdiasis Abu Musab, al Shabaab's military operations spokesman, said.
Al Shabaab also posted a statement on social media saying the raiding party killed eight people and took two prisoners back over the border.
Albert Kimathi, district commissioner for Dadaab, an area near the Somali border, said the rebels made two simultaneous attacks on police posts. Four people, two of them policemen, were killed and two wounded, he said.
"We are also missing two officers who may have ran away," Kimathi said.
Kenyan troops are part of the African Union peacekeeping force battling al Shabaab rebels, who are linked to al Qaeda.
Shabaab has been substantially weakened in the last two years, losing Mogadishu and swathes of central and southern Somalia to the African force, but the rebels have managed to mount raids across the border with Kenya.