Israel intensified strikes on Gaza hours after a ceasefire and hostage release deal was announced, residents and authorities in the Palestinian enclave said, as mediators sought to quell fighting ahead of the truce's start on Sunday.

DOHA/JERUSALEM (Reuters) - Israel and Hamas agreed to a deal to halt fighting in Gaza and exchange Israeli hostages for Palestinian prisoners, an official briefed on the deal told Reuters on Wednesday, opening the way to a possible end to a 15-month war that has upended the Middle East.

The accord outlines a six-week initial ceasefire phase and includes the gradual withdrawal of Israeli forces from the Gaza Strip and release of hostages held by Hamas in exchange for Palestinian prisoners held by Israel.