Afghanistani officials said on Friday Hafiz Saeed, Islamic State's leader for the group's Khorasan Province in the Af-Pak region, was killed in an airstrike.

The confirmation comes a day after the US State Department designated the Isis affiliate in Afghanistan and Pakistan a terrorist organisation.

The high-ranking official of Afghanistan's Achin district told Tolo News Saeed, formerly a leader of the Pakistan Taliban wing, known as Tehreek-e-Taliban Pakistan, was killed in a US drone strike in the Nangarhar province. It is not clear from the report when the Isis leader was killed.

The official's statement confirms reports from last July that had claimed Hazif Saeed was killed in an airstrike. US officials had expressed doubt over the claims at the time.

In April, reports had said the Isis chief had been killed in Pakistan while trying to assemble an improvised explosive device. However, the reports were not confirmed. 

Saeed had pledged allegiance to Islamic State in January last year as the terror group announced its presence in the Afghanistan-Pakistan border region.

 On Thursday, the US State Department gave Isis Khorasan Province the designation of a "Foreign Terrorist Organisation" (FTO) under Section 219 of the Immigration and Nationality Act.

Since its formation in January 2015, the Isis affiliate in the region has "carried out suicide bombings, small arms attacks and kidnappings in eastern Afghanistan against civilians and Afghan National Security and Defence Forces, and claimed responsibility for May 2015 attacks on civilians in Karachi, Pakistan," the US State Department said on its website