Islamic State fighters stormed a police base in eastern Afghanistan Saturday, killing at least six officials in a pre-dawn attack, months after the government claimed to have defeated the group.
The attack in Haska Mina district in Nangarhar comes a day after three worshippers were killed and 70 others wounded in a bombing inside a mosque during Friday prayers in the restive province.
"The district police chief Shah Mahmood was martyred along with five other policemen" in Saturday's attack, Ataullah Khogyani, spokesman for Nangarhar 's governor told AFP.
"Eleven Daesh fighters were also killed and seven others were wounded," he added, using the Arabic acronym for the group.
IS fighters are making inroads into Afghanistan, winning over sympathisers, recruiting followers and challenging the Taliban on their own turf, primarily in the country's east.
But in March Afghan President Ashraf Ghani announced that the militants had been defeated after local security forces claimed victory in a months-long operation against the group.
The group also intermittently airs propaganda through a mobile radio station, which the government claimed to have destroyed in an air strike in February.
"An attack deliberately targeting civilian members of a community praying together in a mosque can never be justified and highlights the perpetrators' intent to destroy lives, and spread terror among the civilian population," the UN said in a statement.
The Taliban , which is in a much stronger position than IS in Afghanistan, distanced itself from the attack and no other group has so far claimed responsibility.
American officials said Friday President Barack Obama has ordered the US military to tackle the resurgent Taliban more directly -- in tandem with Afghan allies, ratcheting up a 15-year conflict he had vowed to end.