Egyptian officials say Sunni Muslim villagers have killed four Shiites they said were trying to spread their version of Islam.

The officials said the four were beaten to death west of Cairo. It's one of the most serious sectarian incidents in Egypt in recent months.

A mob surrounded a house Sunday, threatening to set it on fire if 34 Shiites inside did not leave the village before sunset, the officials said. When they refused, villagers attacked the house and killed four of them, the officials said.

The officials spoke on condition of anonymity because they were not authorized to brief reporters.

Sectarian violence has increased over the past two years, but usually the targets of Muslim extremists have been Christians, not Shiites, who have only a small presence in Egypt.