President Xi Jinping has sent his condolences to Egyptian President Abdel-Fattah al-Sisi over Sunday's deadly terrorist attack that killed 25 people at a church in Cairo.

In the message sent on Tuesday, Xi extended his sincere condolences to the bereaved families and those wounded in the attack.

China firmly opposes terrorism of all forms and strongly condemns the grave terrorist attack, Xi said.

China stands ready to continuously and firmly back efforts made by the Egyptian government to fight terrorism and maintain national security and stability, Xi added.

A bomb went off inside the church in Cairo's Abassiya neighborhood that was full of worshippers attending Sunday mass. The attack left 25 people dead and 49 others injured.