Israel’s security cabinet rejected U.S. Secretary of State John Kerry’s proposal Friday for a cease-fire to end the Gaza conflict.

An Israeli government official told Reuters that the security cabinet wants changes to be made to Kerry’s plan, the details of which have not been released. Hamas hasn’t said whether it would agree to the cease-fire.

Kerry has been trying to end the 18 days of fighting between Israel and Gaza in which more than 840 Palestinians and 35 Israelis have been killed.