MINYA, Egypt (Reuters) - Two Egyptian policemen were shot dead on Tuesday as they stood guard at a Coptic Christian church in a city south of Cairo, witnesses and a local security source said.

The policemen were killed instantly after being shot by masked men, the source and the witnesses said. The website of Egypt's flagship Al-Ahram newspaper also reported the two deaths.

Egypt's Coptic Christmas falls on Wednesday this year and security is typically tightened at churches ahead of the holiday.

The country's Coptic Christians makes up about 10 percent of the population of 85 million. The community has largely coexisted peacefully with the majority Sunni Muslims for centuries.

Following the army's ouster of President Mohamed Mursi of the Muslim Brotherhood in July 2013, a number of churches and Christian properties were burned and destroyed in the impoverished south that is home to many Christians.

The Brotherhood said at the time it had nothing to do with attacks on Christians and accused the army of cynically using the minority population to justify a fierce security crackdown.

(Writing by Maggie Fick; Editing by Michael Perry)