The Islamic State group has claimed responsibility for a suicide bombing that killed the governor of Afghanistan's northern Balkh province and two other people at his office.

The regional affiliate of IS — known as the Islamic State in Khorasan Province — is a key rival of the Taliban. The militant group has increased its attacks in Afghanistan since the Taliban takeover of the country in August 2021. Targets have included Taliban patrols and members of Afghanistan’s Shiite minority.

Thursday's attack in the city of Mazar-e-Sharif killed three people, including governor Daud Muzmal, and injured four others, said local police spokesman Mohammad Asif Waziri.

The Islamic State late Thursday claimed responsibility for the attack, naming the assailant as Abdul Haq al-Khorasani.

It said Khorasani passed through all security measures to enter the official building and carry out the attack.

Zabihullah Mujahid, the Taliban's chief spokesman, said Muzmal was killed “by the enemies of Islam.” He said an investigation is underway, but provided no further details.

Muzmal is one of the most senior Taliban officials to have been killed since they took power in mid-August 2021 as U.S. and NATO forces withdrew from Afghanistan after 20 years of war.

In recent months, the Taliban cracked down on IS. Their security forces killed several regional members, including leaders, in separate operations in February.

Also Read: UN: Afghanistan is world's most repressive country for women

Taliban forces have also detained IS members, including foreign nationals planning deadly attacks, during raids, according to Mujahid.

In January, eight IS militants were killed and nine others arrested in raids targeting key figures in Kabul and Nimroz provinces.