Hamas stood by its demand on Tuesday that Israel fully end its assault on Gaza under any deal to release hostages, and said U.S. President-elect Donald Trump was rash to say there would be “hell to pay” unless they go free by his January 20 inauguration.

Officials from the Islamist group and Israel have been holding talks with Qatari and Egyptian mediators in the most intensive effort for months to reach a ceasefire in Gaza.

The outgoing U.S. administration has called for a final push for a deal before Joe Biden leaves office, and many in the region now view Trump’s inauguration as an unofficial deadline.

But with the clock ticking, both sides accuse the other of blocking a deal by adhering to conditions that torpedoed all previous peace efforts for more than a year.

Hamas says it will free its remaining hostages only if Israel agrees to end the war and withdraw all its troops from Gaza. Israel says it will not end the war until Hamas is dismantled and all hostages are free.

“Hamas is the only obstacle to the release of the hostages,” the director general of Israel’s foreign ministry, Eden Bar Tal, told a briefing with reporters, saying Israel was fully committed to reaching a deal.

Hamas official Osama Hamdan, who held a news conference in Algiers, said Israel was to blame for undermining all efforts to reach a deal.

While he said he would not give details about the latest round of negotiations, he reiterated the Hamas conditions of “a complete end to the aggression and a full withdrawal from lands the occupation invaded.”

Commenting on Trump’s threat that there would be “hell to pay” unless all hostages were freed before the inauguration, Hamdan said: “I think the U.S. president must make more disciplined and diplomatic statements.”

Israel has sent a team of mid-ranking officials to Qatar for talks brokered by Qatari and Egyptian mediators. Some Arabic media reports said David Barnea, the head of Mossad, who has been leading negotiations, was expected to join them. The Israeli prime minister’s office did not comment.