Suspected separatist rebels tossed grenades into a mosque during morning prayers Friday, killing at least four Muslim worshippers, police said.

The attack came a day after Sri Lanka held its presidential election, which was boycotted by the Tamil Tiger rebels.

"Two grenades were thrown at the mosque that killed four people and wounded 10 others," said Nimal Lewke, deputy inspector general of police.

There were no other immediate details of the attack in the city of Akkaraipattu, 140 miles east of the capital, Colombo.

During the two decades of civil war, the mainly Hindu rebels have occasionally carried out attacks against Muslims — the majority religion in Sri Lanka — including an August 1990 massacre of 130 Muslims at two mosques on the same day.

The rebels started fighting in 1983 for a separate Tamil homeland in the northeast. The war eased after a 2002 cease-fire and an uneasy truce has been holding since then.