The fate of a ceasefire deal between Israel and Hamas is "largely a question that is going to be answered" by the leader of the Palestinian militant group, Deputy CIA Director David Cohen said on Wednesday.

Cohen did not refer to Hamas' leader, Yahya Sinwar, by name. The Israelis were showing seriousness in the negotiations, Cohen told an intelligence and national security summit in Washington.

Mediators from the U.S., Egypt and Qatar have been working to strike a deal between the sides and prevent a broader regional war.

On those efforts, Cohen said: "There may be episodes where people would step back from the brink, but I don't think anybody can be confident that that effort to control escalation is something that ... any party in that region" can control.