KABUL, Afghanistan (AP) — A suicide bomber struck at a center of Taliban power Wednesday, setting off a blast at a government ministry in the Afghan capital of Kabul. At least four people were killed, a Taliban official said.

The afternoon explosion took place as workers and visitors were praying inside a mosque of Afghanistan’s Interior Ministry, which is responsible for security and law enforcement in the country. The ministry is on Kabul’s main road next to Kabul International Airport, and is in its own fortified compound.

A Taliban-appointed spokesman for the ministry, Abdul Nafi Takor, said in a tweet: “Unfortunately this afternoon, around 1:30 pm, there was an explosion in a sub mosque at the Ministry of Interior, as a result four worshippers were martyred and 25 others were wounded. The incident is under investigation, we will share the details with the media when it is done.”

He said earlier that the blast happened as ministry workers and visitors were praying.

Nobody immediately claimed responsibility for the explosion, but the Islamic State group affiliate in Afghanistan, the chief rival of the Taliban, has been waging a campaign of violence targeting the Taliban and minority Shiites that has intensified since the Taliban took power in August 2021.

The attack on a government building inside a fortified compound is a serious blow to the Taliban, which has been trying to contain threats to its power and project an image of legitimacy, control and strength since it seized power.

The Emergency Hospital in Kabul said it began receiving patients at around 2:00 pm with injuries and burns, but that initially there was no news of an attack or explosion.

“A few minutes later, the number of injured people arriving increased and they reported seeing a man detonate a device,” said Emergency’s acting country director, Dejan Panic. “It was a suicide attack.”

Panic said the hospital received 20 wounded, all adult males. Of those, 16 were admitted and two were dead on arrival. The number could increase, he said: “The operating theatres are working and we have activated mass casualty procedures.”

The mosque blast follows last week’s suicide bombing at an education center in Kabul that killed as many as 52 people, according to a tally compiled by The Associated Press, more than twice the death toll acknowledged by Taliban officials.

Earlier this year, United Nations experts said the main military threat to the Taliban came from IS and guerrilla-style attacks by former Afghan government security personnel.

Their report said the presence of IS, al-Qaida and “many other terrorist groups and fighters on Afghan soil” was raising concerns in neighboring countries and the wider international community.

In 2020, the IS affiliate attacked a Kabul maternity hospital that killed 24 people, including newborn babies and mothers. In 2021, before the Taliban takeover, the group attacked a school, killing more than 90, most of them schoolgirls.