Egypt has extended by another three months a nationwide state of emergency, citing security reasons.

The latest extension, which will commence on January 13 under a decree issued by President Abdel Fattah el-Sisi on Tuesday, comes after two deadly attacks on Friday against Coptic Christians in Helwan district, south of the capital, Cairo.

State news agency MENA said the move was taken to allow security forces to "take (measures) necessary to confront the dangers and funding of terrorism and safeguard security in all parts of the country".

Egyptian authorities first imposed a nationwide state of emergency in April 2017, after two church bombings killed at least 45 people. Similar extensions were announced in July and October last year.