CAIRO — Top U.S., European and Arab envoys visited a jailed Muslim Brotherhood leader Monday on a mission to ease tensions between Egypt’s military-backed government and supporters of ousted Islamist President Mohamed Morsi.

No details of the meeting emerged, but a European Union official spoke of confidence-building measures, and the two rival camps appeared to be facing critical choices 33 days after the military overthrew democratically elected Morsi.

For the military, failure to disperse the Islamists’ Cairo sit-ins peacefully would leave it little choice but to use force, provoking a bloodbath that would tarnish its image and cost it world support. For the Muslim Brotherhood, a deadly confrontation would risk a ban from politics and a sweeping crackdown.

Already, some 250 people have been killed since Morsi’s ouster.

The talks between U.S. Deputy Secretary of State William Burns and Khairat el-Shater took place in the prison where the Muslim Brotherhood figure is being held.

Burns was accompanied by the foreign ministers of Qatar and the United Arab Emirates, and EU envoy Bernardo Leon.

Meanwhile, U.S. Sens. John McCain and Lindsey Graham arrived in Cairo on Monday at President Barack Obama’s request to press senior Egyptians for a quick return to civilian rule.