WASHINGTON (NEXSTAR) — The terror group Hamas has a new leader, and U.S. Secretary of State Antony Blinken said he has the power to make a ceasefire deal happen. 

Yahya Sinwar is replacing the leader who the group says was killed in Iran last month by an Israeli airstrike.

“He continues to be the person that calls the shots for Hamas,” said Matthew Miller, a U.S. State Department spokesperson.

Miller said Sinwar’s new role doesn’t really change anything. He has been the terror group’s top leader in Gaza and masterminded the Oct. 7th attacks in Israel.

“Sinwar is a brutal terrorist with blood on his hands, including the blood of American citizens,” Miller said. 

However, Miller said Sinwar is the key to getting a ceasefire and hostage agreement.

“We are in the final stages hopefully of a ceasefire deal,” he said.

That’s the most optimistic U.S. officials have been of the deal, but they also warn escalation in the region could derail any progress.

“No party should take any steps to escalate this conflict,” Miller said.

Tensions in the Middle East have intensified, following Israel’s assassinations of top leaders of Hamas and Hezbollah, which are proxies of Iran.

“Not going to speak for what Iran will or will not do,” said White House Press Secretary Karine Jean-Pierre. 

White House officials said Wednesday the U.S. and its allies are engaged in “intensive diplomatic efforts” to try to avoid an all-out regional war.

“Urge de-escalation,” Jean-Pierre said. “That’s what we want to see.”

The U.S. recently increased its own military presence in the region, including moving a fighter jet squadron and maintaining an aircraft carrier there.

Gaza continues to face a severe humanitarian crisis as the war limits access to critical medical supplies, food and water. The Health Ministry said the death toll there is nearly 40,000, but it doesn’t distinguish between military and civilian deaths.