CAIRO, June 16 (Reuters) - The Egyptian army will not interfere in the internal affairs of other countries, the state news agency quoted a military source as saying on Sunday, one day after President Mohamed Mursi backed the idea of a no-fly zone in Syria.

"The Egyptian army is to protect Egypt and its national security only ... The Egyptian army will not interfere in the internal affairs of other countries and will not be lured or used in any regional conflicts," the military source said.

A military spokesman declined to comment.

The remarks came one day after Mursi cut all diplomatic ties with Damascus, backed a no-fly zone over Syria and said: "Egypt, its nation, leadership ... and army, will not abandon the Syrian people until it achieves its rights and dignity."

(Reporting by Asma Alsharif; Editing by Robin Pomeroy)