A Palestinian official close to the negotiations said on Wednesday that mediators had narrowed gaps on most of the agreement's clauses.
He said Israel had introduced conditions which Hamas rejected but would not elaborate.
On Tuesday, sources close to the talks in Cairo, the Egyptian capital, said an agreement could be signed in coming days on a ceasefire and a release of hostages held in Gaza in return for Palestinian prisoners held by Israel.
Medics said an Israeli air strike killed at least 10 people in a house in the northern town of Beit Lahiya while six were killed in separate air strikes in Gaza City, Nuseirat camp in central areas, and Rafah near the border with Egypt.
In Beit Hanoun in the northern Gaza Strip, medics said four people were killed in an air strike on a house.
There was no immediate comment from the Israeli military spokesman.
Israel's military campaign against Hamas has displaced most of the Gaza Strip's population. (AP PHOTO)
Israeli forces have operated in the towns of Beit Hanoun and Beit Lahiya as well as the nearby Jabalia camp since October, in a campaign the military said aimed to prevent Hamas militants from regrouping.
Palestinians accuse Israel of carrying out acts of "ethnic cleansing" to depopulate the northern edge of the enclave to create a buffer zone.
Israel denies it.
Hamas does not disclose its casualties, and the Palestinian health ministry does not distinguish in its daily death toll between combatants and non-combatants.
On Wednesday, the Israeli military said it struck a number of Hamas militants planning an imminent attack against Israeli forces operating in Jabalia.
Later on Wednesday, Muhammad Saleh, director of al-Awda Hospital in Jabalia, said Israeli shelling in the vicinity damaged the facility, wounding seven medics and one patient inside the hospital.
The Israeli military had no immediate comment.
In the central Gazan camp of Bureij, Palestinian families began leaving some districts after the army posted new evacuation orders on X and in written and audio messages to mobile phones of some of the population there, citing new firing of rockets by Palestinian militants from the area.
The US administration, joined by mediators from Egypt and Qatar, has made intensive efforts in recent days to advance the talks before US President Joe Biden leaves office next month.
In Jerusalem, Israeli President Isaac Herzog met Adam Boehler, US president-elect Donald Trump's designated envoy for hostage affairs.
Trump has threatened that "all hell is going to break out" if Hamas does not release its hostages by January 20, the day Trump returns to the White House.
CIA director William Burns was due in Doha on Wednesday for talks with Qatari Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani on bridging remaining gaps between Israel and Hamas, other knowledgeable sources said.
Israeli negotiators were in Doha on Monday looking to bridge gaps between Israel and Hamas on a deal Biden outlined in May.
There have been repeated rounds of talks over the past year, all of which have failed, with Israel insisting on retaining a military presence in the Gaza Strip and Hamas refusing to release hostages until the troops pulled out.
The war in the strip, triggered by a Hamas-led attack on communities in southern Israel that killed 1200 people and included more than 250 being abducted as hostages, has sent shockwaves across the Middle East and left Israel isolated internationally.
Israel's campaign has killed more than 45,000 Palestinians, displaced most of the 2.3 million population and reduced much of the coastal enclave to ruins.
