Middle East live updates: Biden confirms ceasefire deal reached

A ceasefire agreement between Israel and Hamas has hit a last-minute snag, with both sides at odds over the Philadelphia axis, a piece of land separating the Gaza Strip and Egypt, according to an Israeli source with direct knowledge of the negotiations.

"The Israeli negotiating team was recently informed that the Hamas terrorist organization decided at the last minute to make new demands - this time regarding the Philadelphia axis, in contrast to the maps that have already been approved by the cabinet and American mediators. Israel strongly opposes any changes to these maps," the Israeli source told ABC News.

Two sources close to the ceasefire negotiations tell ABC News Hamas has given the green light to the agreement.

"We are very close," the sources said. "The goal (is) an agreement today or tomorrow."

-ABC News' Jordana Miller

The Israel Defense Forces and Israeli intelligence agencies coordinated to attack around 50 targets across the Gaza Strip in the previous 24 hours, the IDF said in a Wednesday morning post to X.

The attacks targeted Hamas and Palestinian Islamic Jihad, the IDF said.

It reported strikes in Gaza City in the north of the strip, Khan Younis in the south and Deir al-Balah in central Gaza.

The targets included "terrorist cells, weapons depots, underground infrastructure, anti-tank positions and military structures," the IDF said.

The latest wave of strikes came as ceasefire negotiators in Qatar reportedly neared a deal to pause -- and eventually scale down -- the 15-month-old war.

Israel and the highest ranks of Hamas have now agreed to the core elements of the hostage release-ceasefire deal on the table, but both sides are continuing to haggle over the details of the proposal, according to two officials familiar with the negotiations.

The outstanding differences are seen as relatively minor, but talks are expected to continue into Wednesday, the officials said.

Many of the items that are still being ironed out are tied to stubborn sticking points that have emerged in the past, like the operation of the Rafah border crossing and Israeli security concerns connected to the movement of displaced Palestinians back to their homes in northern Gaza.

The disagreements are unlikely to derail progress at this point, according to the officials.

Two of the three Americans that are possibly alive inside Gaza are poised to be released in the initial days or weeks of the ceasefire if an agreement is reached, but an official said they expect the releases will happen slower than they did during the truce in November 2023.

While they don’t have recent proof of life for the two Americans, the assumption is that they and most -- but not all -- of the 33 hostages freed under the deal will be returned alive.

-ABC News' Shannon K. Kingston