The United States said Saturday it had conducted its deepest-ever analysis of Israel's security needs and believed a two-state solution with Palestinians could include sufficient guarantees to safeguard the Jewish state.

President Barack Obama and Secretary of State John Kerry revealed some details of the US effort to convince Israel that its security could be ensured in any final peace deal.

Kerry said US Middle East security envoy General John Allen was working closely with Israeli forces to test scenarios and work out how to satisfy Israeli needs for years to come.

"He is helping us make sure that the border on the Jordan River will be as strong as any in the world, so that there will be no question about the security of the citizens, Israelis and Palestinians, living to the west of it," Kerry said at the Brookings Institution's Saban Forum.

"Never before has the United States conducted such an in-depth analysis of Israel's security requirements that arise from a two-state solution," Kerry said.

Obama said earlier at the same event that Allen had concluded "that it is possible to create a two-state solution that preserves Israel's core security needs."

"That's his conclusion, but ultimately he's not the decision-maker here, Prime Minister Netanyahu and the Israeli military and intelligence folks have to make that determination."

Allen briefed Netanyahu on his conclusions on Thursday.

Kerry said more than 160 US experts were coordinating with the Palestinians and the Jordanians as well as Israelis and running multiple scenarios, including future border issues and terrorism, to pinpoint Israel's needs.

He described the process as a "critical threading of the needle that needs to happen."

"What we put on the table is deadly serious, real."

Kerry said multiple US government, intelligence and military agencies were working with Israelis and Palestinians on security -- which he billed as a make or break issue for his long-running initiative to broker peace between the two sides.

Netanyahu has said that under any peace agreement, Israel "must be able to defend itself, by itself, with our own forces" -- an allusion to the reported debate over security in the Jordan Valley, which separates the West Bank from neighboring Jordan.

Israel has always insisted that in any final agreement it would have to maintain a military presence there, and has rejected outright the idea of any third party involvement.

Obama also warned that, in the event of a final agreement, the Palestinians would have to accept Israel would require a "transition period" to ensure that the West Bank did not become a security threat akin to Hamas-ruled Gaza.

"This transition period requires some restraint on the part of the Palestinians as well. They don't get everything they want on day one," he said.

The State Department, meanwhile, said that Kerry would meet Israeli Foreign Minister Avigdor Lieberman on Sunday morning in Washington.