At least four militants of the Islamic State (IS) were killed in a US drone strike in Afghanistan’s Nangarhar province, an official said on Sunday.

“An international forces’ plane fired two missiles in Achin district Saturday night,” Xinhua news agency quoted an official as saying.

The Afghan security forces have beefed up operations against militants, he said.

The Achin district bordering Pakistan has been the scene of heavy clashes between the IS militants and security forces backed by pro-government local militiamen over the past couple of months.