The United States said Wednesday that Hamas’ demands were thwarting its push for a cease-fire with Israel, signaling the fighting would go on as the United Nations accused both sides of war crimes and Hezbollah unleashed a rocket barrage to avenge a top commander’s killing that threatened wider escalation.

Secretary of State Antony Blinken said the Palestinian militant group had requested “numerous” changes to the Washington-backed plan to end fighting in the Gaza Strip and release hostages taken from Israel on Oct. 7.

“Some of those are workable changes, some are not,” Blinken said in Qatar, speaking on his latest round of shuttle diplomacy to try and advance a deal that neither warring party has fully embraced.

Giving the briefing hours after Hamas delivered its formal response, he said that Washington would keep working with meditators to try and secure an agreement.

Hezbollah’s retaliatory attacks

Blinken’s comments came during a day of intense activity, both military and diplomatic, across the Middle East.

Earlier Wednesday, the Lebanese militant group Hezbollah, a Hamas ally that is also backed by Iran, launched a “massive” volley of some 160 missiles into Israel, the Israeli military said.

This marked a significant flare-up on Israel’s northern front with Lebanon, which many observers fear could escalate into full-blown regional war.

The Israel Defense Forces told NBC News that one of the missiles struck a factory in Kibbutz Sasa, some 3 miles from the border. Most of the rockets were intercepted or fell in open country, and one Israeli jet struck back at a launcher inside Lebanon, the IDF said.

Hezbollah’s Al-Manar TV station said the barrage was in retaliation for Israel’s killing of one of its commanders, Taleb Sami Abdullah.

Also known as Hajj Abu Taleb, 55, he was the most senior figure from the militant group killed since the fighting began, and had been in charge of a unit that oversees parts of the southern border region.

He was killed in an Israeli airstrike on what the IDF called a “command and control center” in the town of Joya late Tuesday. The attack also killed another three operatives, the IDF said in a statement accompanied by video of the strike.