Egypt's President Abdel Fattah al-Sisi said a three-month state of emergency would be imposed after two deadly bombings hit Coptic churches on Sunday, killing at least 44 people.

In a televised speech addressing the nation, Sisi declared a three-month countrywide state of emergency, subject to parliamentary approval, and called for national unity and urged the media to refrain from coverage that could be harmful.

"Deal with the issue with credibility, and responsibility and awareness," he said of the media coverage. "It's not right what I'm seeing being repeated on all of our channels, and you know this hurts Egyptians."

Sisi also ordered troops be immediately deployed to assist police in securing vital facilities, a rare move for the general-turned-president, who as defence chief led the military's 2013 ouster of the Muslim Brotherhood's President Mohamed Mursi.

Deflecting Western criticism that he has suppressed political opposition and human rights activists since he was elected in 2014, Sisi has sought to present himself as an indispensable bulwark against terrorism in the Middle East.

"The attack...will only harden the determination (of the Egyptian people) to move forward on their trajectory to realise security, stability and comprehensive development," Sisi said in a statement.