BERLIN — Syrian opposition leaders agreed on Monday to meet with Secretary of State John Kerry this week in Rome, backing off from their threat to boycott the session after a day of public and private lobbying by Kerry to persuade them to attend what is expected to be a centerpiece of his nine-country tour.

The opposition leaders agreed to meet with Kerry after he signaled he has unspecified new strategies for ousting Syria’s president, Bashar al-Assad. That thrust Kerry to the forefront of efforts to end a civil war that has cost tens of thousands of Syrian lives.