At least 29 people were killed and many others injured in a suicide attack on a Shia mosque in the western Afghan city of Herat on Tuesday.

According to the reports, two attackers entered the mosque and started firing. A suicide bomber detonated explosives and the other person, a gunman, threw grenades at worshippers.

"Two attackers entered the mosque and started shooting and throwing grenades at people," a worshipper at the mosque said.

After the attack, dozens of angry residents confronted police, complaining that they had failed to intervene while the attack was in progress.    

No terror group has taken the responsibility of the attack yet.

During the Muslim holy month of Ramadan in June this year, six people were killed and eight injured when an Islamic State suicide bomber struck a Shia mosque in Kabul.