Pakistan police said three officers were killed on Friday near the northwestern Afghan border during a gun battle that also killed three militants, in an uptick in violence raising security concerns ahead of national elections early next year.
The attack came within two days of another such militant attack in the region which killed 23 Pakistani soldiers in Dera Ismail Khan district, near the country's lawless tribal districts bordering Afghanistan.
Friday's attack occurred in the adjacent Tank district when one of several militants first exploded himself at the main entrance of a police office and residence block and the others stormed in, said police official Iftikhar Shah.
"Our force on guard engaged them in a gun battle for hours," and two more police officers were wounded, he said.
Provincial police chief Akhtar Hayat said three of the attackers were killed. "We are searching for the rest of them, including two who suffered wounds," he said.
A little-known militant group that identified itself as Ansar-ul-Islam claimed responsibility, saying it was their first attack, according to a statement sent to a Reuters reporter.
The police didn't verify the authenticity of the claim.
The Pakistani military has conducted several operations against the militants, especially in Waziristan region next to the district where the latest attacks occurred, which once served as a headquarters of the local and foreign terrorists.


Iran rejects Trump's talk of negotiation as Israel and Iran launch airstrikes
Cyprus has opened discussion with UK over its bases, president says
Netanyahu seeks to avoid snap vote as Iran war gives no boost in polls
Luxury Paris hotel near Elysee reopens after fire forces brief closure
Germany renews push for sugar tax and energy drinks ban for children
