WASHINGTON (NEXSTAR) -- President-elect Donald Trump is threatening the terror group Hamas to release its remaining hostages in Gaza before his inauguration Jan. 20.  "If they're not back by the time I get into office, all hell will break out in the Middle East," Trump said. However, Trump would not elaborate on what actions he would take. "It will not be good for Hamas and it will not be good, frankly, for anyone," he said.  Israel announced Wednesday that troops recovered the remains of more hostages. Officials said roughly 100 hostages remain in Hamas hands, but as many as half are presumed dead. "Please don't let any hostage stay behind," said Merav Leshem Gonen, the mother of hostage Romi Gonen. Trump's special envoy to the Middle East, Steve Witkoff, is part of the effort to reach a ceasefire and hostage release deal. Witkoff said the negotiations are making progress. "So hopefully it'll all work out and we'll save some lives," Witkoff said. Trump and President Joe Biden are urging Israel and Hamas to accept a deal before the inauguration. Israel wants assurances that the hostages are still alive, but Hamas said it doesn't know who is alive or dead. "We're very close to a ceasefire and hostage agreement," said U.S. Secretary of State Antony Blinken. Blinken said if negotiations do slide past Jan. 20, his team has already made arrangements for Trump's team to take over. "The world doesn't stop because we have a transition," Blinken said. A growing group of Israeli soldiers is refusing to continue fighting in Gaza. The troops said they disagree with the way Israel is conducting the war and don't think it will bring home the hostages. The group said it hopes to pressure the Israeli government into a ceasefire.