Recent U.S. airstrikes assisted in destroying 30 militants and a top leader of a fledging Islamic State of Iraq and Syria affiliate in Afghanistan, Afghan authorities said Saturday.

The strikes may have struck a major blow to an insurgent Taliban fighter group.

"With the killings of Hafiz Sayeed, Gul Zaman and Shahidullah Shahid, who were the high-profile figures of Daesh [the Arabic pejorative for the Islamic State] in Afghanistan, we have destroyed the base of ISIS," said Abdul Hassib Sediqi, according to the Associated Press.

Sediqi said that the Afghans had created their own special intelligence unit to target an Islamic State affiliate in three of its provinces, including Nangarhar, which borders Pakistan.

While U.S. Army Col. Brian Tribus, a spokesman for U.S. Forces-Afghanistan, confirmed Americans carried out an airstrike in Nangarhar's Achin District Friday, he declined to comment further. U.S. officials also declined to confirm the Afghan claims.

This strike follows an earlier U.S. airstrike which Afghan officials report hit the affiliate's second-highest official, Gul Zaman, and six others, including a former Pakistani Taliban spokesman named Shahidullah Shahid, according to the AP.

NATO officials said they would issue a statement later Saturday on the authenticity of the claim.

No photographs or other evidence were offered to prove the strikes killed the Islamic State affiliate's top leaders, but Sediqi said Afghan authorities had verified that a corpse from Friday's strike was Sayeed.

However, militants have not discussed the strikes online. The Islamic State is a self-proclaimed "caliphate" that has large swaths of territory in Syria and Iraq, and affiliated militants in northeastern Nigeria, and parts of Libya and Egypt. They have been growing their ranks through a sophisticated social media network replete with slick, Hollywood-style beheading videos.

The AP reports that disenchanted Taliban members have joined with the Islamic State and began to raise the black flag in parts of the country that the U.S. invaded after the Sept. 11, 2011 attacks.

The number of Islamic State supporters in the Afghan-Pakistan region has remained small, according to analysts, as the group faces competition with local militants.

"Daesh activities have been totally disturbed here and it is not easy for them to replace all these high-ranking figures any time soon," said Sediqi.