CAIRO (Reuters) - Two U.S. senators visiting Cairo on Tuesday urged both sides in Egypt's political crisis to start a national dialogue and to avoid violence.

Senators Lindsey Graham and John McCain, on a mission for U.S. President Barack Obama to help resolve the crisis brought on by the overthrow of President Mohamed Mursi last month, also called for the release of political prisoners.

It would be the wrong time to cut off military aid to Egypt as a response to Mursi's removal by the army, they told a news conference.

(Reporting by Maggie Fick, Writing by Angus MacSwan; Editing by Michael Georgy)