U.S. and Arab mediators have made some progress in their efforts to reach a ceasefire accord between Israel and Hamas in Gaza, but not enough to seal a deal, Palestinian sources close to the talks said on Thursday.

As talks continued in Qatar, the Israeli military carried out strikes across the enclave, killing at least 23 people on Thursday, Palestinian medics said.

The deaths brought to 76 the number of people killed by Israeli strikes across Gaza in the past 24 hours, according to the territory’s health ministry.

Qatar, the U.S. and Egypt are making a push to reach a deal to halt fighting in the 15-month conflict and free remaining hostages held by Islamist group Hamas before President Joe Biden leaves office.

“We’re making some real progress,” Biden told reporters at the White House. “I’m still hopeful that we’ll be able to have a prisoner exchange,” he said, adding Hamas was getting in the way of that. The president said he met with negotiators on Thursday.

On Thursday, a Palestinian official close to the mediation effort said the absence of a deal so far did not mean the talks were going nowhere and this was the most serious attempt so far.

“There are extensive negotiations, mediators and negotiators are talking about every word and every detail. There is a breakthrough when it comes to narrowing old existing gaps but there is no deal yet,” he told Reuters, without giving further details.