A huge bomb blast on Friday at one of the biggest mosques in western Afghanistan killed at least 18 people, including an influential cleric who earlier this year called for those who commit “the smallest act” against the government to be beheaded.

Images posted on Twitter showed what appeared to be blood-stained bodies scattered around the compound of Gazargah Mosque in Herat city.

Violence has largely declined since the Taliban returned to power last year, but several bomb blasts — some targeting minority communities — have rocked the country in recent months, many claimed by the militant Islamic State (IS) group.

At least 18 people were killed and 23 wounded in Friday’s blast, said Hameedullah Motawakel, spokesman for the governor of Herat province, in a text message to media.

Government spokesman Zabihullah Mujahid confirmed Mujib ur Rahman Ansari, the imam of the mosque, was among the dead.

“A strong and courageous religious scholar of this country was martyred in a brutal attack,” he said on Twitter.

Ansari was an influential cleric known for his fiery speeches.

In July, during a religious gathering in Kabul, he strongly defended Afghanistan’s new Taliban rulers.

“Whoever commits the smallest act against our Islamic government should be beheaded,” he had said.

“This (Taliban) flag has not been raised easily, and it will not be lowered easily.”

Before the Taliban returned to power in August last year, Ansari was known for his tirades against the previous US-backed governments.

Ansari is the second pro-Taliban cleric to be killed in a blast in less than a month, after an earlier suicide attack targeted Rahimullah Haqqani at his madrassa in Kabul.

Haqqani was known for angry speeches against IS, who later claimed responsibility for his death.

He had also spoken in favour of girls being allowed to attend secondary school, despite the government banning them from attending classes in most provinces.

Pakistan condemns attack

Later, Pakistan strongly condemned the “heinous” terrorist attack on Guzargah Mosque in which “many precious lives of innocent people have been lost with several injuries”.

“The Government and people of Pakistan extend deepest sympathies and sincere condolences to the bereaved families, and pray for the early recovery of those injured,” a statement issued by the Foreign Office said.

It added that Pakistan condemned terrorism in all its forms and manifestations. “The people of Pakistan stand with their Afghan brothers and sisters in this time of sorrow and grief.”

Several mosques across the country have been targeted this year, some in attacks claimed by IS.

At least 21 people were killed and dozens more wounded on August 17 when a blast ripped through a mosque packed with worshippers in Kabul.

Government officials claim that IS has been defeated but experts say the group is the main security challenge for the country’s current rulers.