Israel and Hamas signaled that a temporary cease-fire in Gaza could be extended beyond Monday to allow for the release of more hostages and prisoners.

U.S. President Joe Biden backed prolonging the war pause, saying it’s allowing for the delivery of “critically needed” aid to Gaza and the recovery of hostages, after another 17 were released by Hamas on Sunday.

The four-day pause brokered by Qatar, which began Friday, provides for Hamas to release 50 hostages in exchange for 150 Israeli-held prisoners — and for Israel to hold its fire for each day that Hamas frees 10 more captives. Hamas has handed over 58 hostages through Sunday.

“This deal is structured so that it can be extended to keep building on these results,” Biden told reporters. “That’s my goal.”

Hamas released a statement on Telegram late Sunday saying it seeks to “extend the truce after the end of the four-day period.” Israel Defense Forces spokesman Daniel Hagari said the military is preparing for the next stage of fighting, but hopes “we can bring home as many hostages as possible before that happens.”

According to the White House, Biden and Netanyahu agreed the work was not yet done. Biden described the negotiations as a day-by-day, hour-by-hour process and said he would continue working until all hostages were free.

“Nothing is guaranteed and nothing is being taken for granted. But the proof that this is working and worth pursuing further is in every smile and every grateful tear we see on the faces of those families who are finally getting back together again. The proof is little Abigail,” the president said.

Netanyahu in a video statement after speaking with Biden, reiterated his offer to extend the cease-fire by an additional day for every 10 hostages Hamas releases. But he also said Israel would resume its offensive against Hamas “with all of its power” once the cease-fire expires.

International mediators led by representatives from the United States and Qatar are trying to extend the cease-fire for as long as possible.