Egypt's president is inaugurating a new cathedral for the Coptic Orthodox Church and one of the region's largest mosques.

Sunday's opening ceremony is a highly symbolic gesture at a time when Islamic militants are increasingly targeting the country's minority Christians.

Abdel-Fattah el-Sissi, a general-turned-president, has made sectarian harmony a cornerstone of his rule, fighting Islamic militancy while advocating equality between the overwhelming Muslim majority and Christians, who account for about 10 percent of Egypt's 100 million people.

The cathedral and mosque were built in Egypt's New Administrative Capital, el-Sissi's brainchild, in the desert east of Cairo.

The inauguration ceremony fell on Christmas Eve for Egypt's predominantly Coptic Orthodox Christians, and just hours after a police major was killed trying to defuse an explosive device near a Cairo church.