An Israeli official said on Sunday that Israeli forces have begun withdrawing from a key Gaza corridor, part of a ceasefire deal with Hamas that is moving ahead. Israel agreed as part of the truce to remove its forces from the Netzarim corridor, a strip of land that bisects northern Gaza from the south. The official spoke on condition of anonymity because he wasn’t authorized to discuss troop movement with the media. It was not clear how many troops Israel had withdrawn on Sunday.

The 42-day ceasefire is just past its halfway point and the sides are supposed to negotiate an extension that would lead to more Israeli hostages being freed from Hamas captivity. But the agreement is fragile and the extension isn’t guaranteed. The sides are meant to begin talks on the truce’s second stage but there appears to have been little progress.