A bomb has exploded in the entrance of a mosque in the Afghan capital Kabul, leaving a “number of civilians dead”, according to the Taliban.
The blast happened as a memorial service was being held for the mother of deputy information minister Zabihullah Mujahid, who later tweeted the attack had claimed lives.
Those killed were outside the gate of the Eidgah mosque, said Taliban spokesman Bilal Karimi.
He did not provide a figure for the number dead and said an investigation was ongoing.
But another Taliban official told the Reuters news agency at least two civilians were killed and three injured.
The rise has raised the possibility of a wider conflict between the two extremist groups.
IS maintains a strong presence in the eastern province of Nangarhar and considers the Taliban an enemy.
It has claimed several attacks against the Taliban, including several killings in the provincial capital of Jalalabad.
Attacks in the capital have so far been rare, but in recent weeks IS has shown signs it is expanding its presence beyond the east and closer toward the capital.
On Friday, Taliban fighters raided an IS hideout just north of Kabul in Parwan province.
The raid came after an IS roadside bomb wounded four Taliban fighters in the area.
Taliban leaders, already under pressure from the international community to renounce ties with groups such as IS and al Qaeda, have denied their militants are active in the country.