Egyptian security officials say five people have been killed in clashes between Muslims and Christians just outside Cairo.

Investigators say they are waiting for autopsy reports to confirm how the five men were killed.

Officials say the clashes on Saturday started when young Muslims drew upside down crosses on an Islamic institute.

Christian onlookers began quarrelling with Muslims nearby and soon residents wielding guns began firing on one another.

A fire also broke out near a church in the Khosoos neighborhood where the clashes took place before dawn.

Christians make up some 10 percent of Egypt's 85 million people.