Gunmen kill eight Kenyans, including five policemen, after ambushing a police patrol near the border with Somalia, police say.
Several people were also wounded in the attack close to the north-eastern town of Liboi, police added.
Liboi is used by Kenya to send supplies to its troops fighting the al-Qaeda-linked al-Shabab group in Somalia as part of an African Union (AU) force.
There are regular attacks along the border from bandits and militants.
It is not clear who carried out the attack.
Al-Shabab has carried out a string of attacks in Kenya - including the siege at the Westgate shopping centre in the capital, Nairobi, in September.
At least 61 people were killed in the attack and some 200 wounded.
Kenya's deputy police inspector, Samuel Arachi, said the security forces had been mobilised to track down the gunmen who carried out the attack near Liboi, about 550km (340 miles) north-east of Nairobi.
Mr Arachi did not give casualty figures, but Kenya's Daily Nation newspaper and the AFP news agency quote unnamed police officers as saying that eight people were shot dead.
"Five [policemen] were killed on the spot when they were ambushed out on patrol, and we are told many bullets were fired on their vehicle," an officer told AFP.
"Three civilians were also killed in the attack."
In May last year, four police officers were wounded in an ambush in the same area.
Kenya sent troops to Somalia in 2011 to fight al-Shabab, saying it threatened regional stability.
The troops were later incorporated into an AU force which now numbers about 18,000.
The force has captured key cities and towns from al-Shabab but the group still controls large swathes of territory in southern Somalia.