Those killed in the Wajir County blast were among 13 officers who had been pursuing suspected extremists who had kidnapped police reservists, the officials said. The officials spoke on condition of anonymity because they were not authorized to share the information.
Police on Friday said a number of gunmen thought to be members of the Somalia-based al-Shabab extremist group stormed Konton center in Wajir East and kidnapped three reservists.
There was no immediate claim of responsibility for the latest attack. Al-Shabab often targets Kenyan security forces. It has vowed retribution for Kenya's deployment of troops to Somalia in 2011 to combat the extremists after they carried out high-profile kidnappings inside Kenya and hurt the country's lucrative tourism industry.
In recent months the al-Qaida-linked al-Shabab has resumed the abductions.
In April the extremist group kidnapped two Cuban doctors in Mandera County and demanded $1.5 million for their return.
In November an Italian volunteer, Silvia Romano, was kidnapped in southern Kenya's coastal region by gunmen linked to al-Shabab. She has not been found.
Follow Africa news at https://twitter.com/AP_Africa
Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.