Reports from Kenya's eastern Garissa region said as many as 20 police officers are feared dead in two attacks by suspected al-Shabab militants.
Local officials said the first attack occurred when a police vehicle ran over a land mine in Yumbis village, injuring at least three policemen.
Later, suspected al-Shabab militants attacked a convoy of police on their way to assist other police. The attackers burned at least four vehicles. Some 20 police officers were reported dead, but details were unclear.
The National Police Service has not confirmed the death toll, saying only that two officers were critically injured, three had minor injuries, and five vehicles were burned. In a statement, the police said an operation to subdue the attackers is "on course" and more information will be supplied as it becomes available.
An al-Shabab spokesman told Reuters news agency that his group was responsible for the attacks.
Al-Shabab has staged several attacks in Kenya in retaliation for Kenya's participation in anti-al-Shabab operations in Somalia, where the militant group is based.
Last month, al-Shabab militants attacked Garissa University College in the same region of Kenya, killing 148 people.