KABUL — US airstrikes have destroyed an Islamic State-operated radio station in a remote part of eastern Afghanistan, officials said Tuesday.

“Voice of the Caliphate’’ radio was destroyed by two airstrikes, according to a US military official, who spoke on condition of anonymity because he was not authorized to brief media on the subject.

Army Colonel Mike Lawhorn, spokesman for the US-NATO mission in Afghanistan, said US forces conducted two ‘‘counter-terrorism airstrikes’’ Monday in Achin district, without elaborating.

An Islamic State affiliate has emerged in Afghanistan over the past year, with a military presence in districts near the border with Pakistan. The radio station was broadcasting illegally across Nangarhar, calling on fighters to join the group and threatening journalists in the provincial capital, Jalalabad.

Afghan officials had said they believed the broadcasts were coming from mobile facilities that could be moved easily back and forth across the mountainous border.

A spokesman for the region’s governor said the strikes killed 21 Islamic State supporters, including five working for the station.

The station was set up in late 2015, following months of fierce fighting between Islamic State militants and the Taliban, who also maintain a significant presence in the region. Although the Islamic State and the Taliban both want to impose a harsh version of Islamic rule, they are bitterly divided over leadership and strategy.

Associated Press