Yemeni President Ali Abdullah Saleh has agreed to an internationally negotiated plan to step down within 30 days in exchange for criminal immunity over his deadly crackdown on protests that have tipped the nation perilously close to civil war, Yemeni officials and opposition leaders said Saturday.

But the canny Saleh has broken many promises in the past, and the latest concession could be another maneuver by a leader who has remained defiant against massive street demonstrations and the defections of top military and government officials.

Yemen’s opposition leaders said they may accept the deal with reservations. But hundreds of thousands of protesters are unlikely to go along. They have been calling for Saleh’s immediate resignation and have voiced little willingness to grant immunity to him or his relatives, including his son, Ahmed, head of the Republican Guard.