“Mujib Rahman Ansari, with some of his guards and civilians, has been killed on their way toward the mosque,” said Herat’s police spokesperson Mahmood Rasoli.

Rasoli did not say how many casualties the blast caused. Al Jazeera Media Network, citing unnamed sources, said 14 people had been killed.

American wire service Associated Press, citing a medic, reported 18 casualties as did Afghan publication Tolo News.

Taliban spokesperson Zabiullah Mujahid, in a Tweet, expressed “strong condolences” over Ansari’s death and said his attackers would be punished.

Mujib Rahman Ansari had spoken strongly in defense of the Taliban at a large gathering of thousands of scholars and elders organised by the group in late June, condemning anyone who stood against their administration.

The Taliban say they have improved security in the country since taking power around a year ago, but there have been several blasts in recent months, some of them targeting busy mosques during prayers.

The United Nations has raised concerns about the growing number of attacks and some blasts have been claimed by a local branch of the Islamic State.

There was no immediate claim of responsibility for Friday’s explosion.

This is a developing story.