Somali militants killed eight Kenyan police with a roadside bomb near the border between the two countries on Saturday, officials said, while another eight died in a bombing the same group carried out in the Somali capital.
Both attacks were claimed by Somali Islamist insurgents, who also kidnapped three Kenyan police reservists on Friday from the same area, in Wajir district in northeast Kenya.
Kenyan military forces have occupied part of southern Somalia along the border since 2011. The Kenyans, along with allied Somali militia, wrested control of the territory from al Shabaab jihadists after a spate of kidnappings on Kenyan soil.
Al Shabaab is fighting the weak, U.N.-backed Somali government and its international allies in a quest to impose strict Islamic law.
The vehicle that was hit by the roadside bomb was carrying 11 policemen, police spokesman Charles Owino told Reuters. A local official said eight were killed.
"Eight bodies were found and taken to Wajir. Two were rescued, but they are in critical condition," said Muhumed Ali Gedi, a member of the local community security team from Wajir who witnessed the rescue mission.
In Mogadishu, al Shabaab detonated two bombs. Police said the first blast, at a busy junction known as K4, was a car bomb intercepted by security services that caused no casualties.
The other blast killed eight people and injured 16, said Abdikadir Abdirahman, the director of Aamin ambulance service.
Abdiasis Abu Musab, al Shabaab's spokesman for military operations, said the group was responsible for the blast in Kenya and the two in Mogadishu.