Afghan officials say at least 15 people have been killed in a suicide bomb attack on a Shi'ite shrine in central Kabul.

Officials say the suicide bomber detonated his explosives near the Abul Fazel shrine as pilgrims gathered to celebrate the Shi'ite holiday of Ashura.

Meanwhile, officials say a second explosion targeted a mosque in the northern city of Mazar-e-Sharif on Tuesday, killing four people. It is not clear whether Shi'ites were also the target of the second attack.

The festival of Ashura is the most significant holiday for Shi'ite Muslims. It marks the martyrdom of Hussein, the grandson of the Prophet Muhammad.

Attacks between Afghanistan's Sunni citizens and minority Shi'ite population have been rare in recent years, though attacks between the two groups are more frequent in neighboring Pakistan.