Amid growing international pressure on Israel to agree to a permanent ceasefire with Hamas or curtail its operations in Gaza, U.K. Foreign Secretary David Cameron squarely rejected such calls in remarks at the Aspen Security Forum in Washington on Thursday.

Cameron, who previously served as prime minister from 2010-2016, said that any ceasefire that leaves Hamas in control of Gaza cannot last and will not ultimately lead to long-term peace.

“People who call for an immediate permanent ceasefire, you need to understand that if you stop now with Hamas still in charge of even a part of Gaza, there can never be a two-state solution,” Cameron said. “So I think it’s important we support Israel while at the same time argue about the importance of international humanitarian law, the importance of reducing civilian casualties. We will make those points over and over again.”

Cameron insisted that a two-state solution remains possible — even if it “feels a long way off” given the national trauma Israel experienced on Oct. 7.

“Ultimately, if you’re a friend of Israel, and I am, long-term security for Israel means not only being strong, not only having strong defenses, it means finding a way where your Palestinian neighbors are also living in peace and security and dignity,” Cameron said. “And ultimately that must mean a two-state solution.”

Looking past the current war, Cameron offered support for the emerging strategy in Washington, including reforming and empowering the Palestinian Authority to retake control of Gaza, with reconstruction assistance from the Arab world. Cameron said that Israel and its allies have to start planning now for how they will execute that strategy.

“It is incredibly difficult, but… the alternatives to a two-state solution are much worse,” he said.

Asked by moderator Jennifer Griffin, a Fox News reporter, whether Israeli Prime Minister Benjamin Netanyahu, with whom Cameron met on a recent visit to Israel, supports a two-state solution, Cameron sighed deeply before responding. 

“Well, you’d have to ask him that question,” Cameron said. “It is in Israel’s long-term security interests. And so friends of Israel have to persuade them of that fact and then judge them by whether the actions they take make it, in the long term, more likely or less likely.”