Saudi police have killed two militants who were planning to carry out a bomb attack, officials in the kingdom say. The two suspects died in a shoot-out with police in the capital Riyadh, a Saudi interior ministry official said. The incident happened at noon (0900GMT), "as the terror operation... was about to be carried out," he said. The authorities believe the attack was timed for the start of the three-day Eid al-Fitr holiday, marking the end of the Muslim holy month of Ramadan. The Saudi news agency SPA says officials are attempting to establish the identity of the two who were killed. "Security forces were able to foil a terrorist operation on the afternoon of the blessed Eid al-Fitr," said a ministry spokesman quoted by SPA. "The security forces were able to disrupt this terror plot by clashing with the terrorists and flushing them out of their dens, which resulted in the death of two of them and the seizure of a car bomb which was ready to be detonated," added the statement. The incident came soon after Saudi Arabia's top religious leader urged people to reject extremism and rally behind the country's leaders. Sheikh Abdulaziz bin Abdullah al-Sheikh told worshippers in Riyadh that suicide bombers threatened the unity of Saudi Arabia. "God intended for Muslims to be a moderate and tolerant people and not inclined to extremism," the grand mufti said to mark the end of Ramadan. More than 50 people - including bombers - have been killed in two suicide bomb attacks in the kingdom over the last six months. Saudi authorities have clamped down heavily on suspected militants since the first attacks on western compounds in Riyadh last May. **PHOTO CAPTION*** Saudi Arabia.