KABUL (AFP) -- Several senior Islamic State group members in Afghanistan -- including a provincial leader -- have been killed in a United States air strike, an official said Sunday.

General John Nicholson, commander of US forces in Afghanistan, said Thursday's strike killed Abdul Rahman, who he claimed was a provincial leader in IS's Afghanistan branch, known as IS-Khorasan Province.

Rahman's death comes a month after US forces killed Abu Sayed, the head of IS-K. That marked the third time in a year that the affiliate had lost its leader.

"The death of Abdul Rahman deals yet another blow to the senior leadership of ISIS-K," Nicholson said in a statement.

"He found out just like those before him that there are no safe havens in Afghanistan. We will hunt them down until they are no longer a threat to the Afghan people and the region," he added.

Nicholson said that three other senior IS-K members had been killed in the strike in Darah-Ye Pech district in the northeastern province of Kunar.

He identified Rahman as IS-K's provincial emir in Kunar and said he had been a "primary candidate" to succeed Sayed as the affiliate's leader following the latter's death, also in an air strike in Kunar, on July 11.

US forces have regularly been targeting IS fighters in Afghanistan since the insurgents gained a foothold in the east of the country in 2015.

The US says it wants to defeat them by the end of the year.

In April, the US military in Afghanistan dropped the so-called Mother Of All Bombs to target IS hideouts in a complex of tunnels and bunkers in eastern Nangarhar province, killing over 90 militants.

IS continues to wreak havoc in the war-torn country though. Earlier this month it claimed an attack on a mosque in Herat that killed 33 worshippers.