Secretary of State John Kerry is finalizing his selection of a team to help shepherd Middle East peace talks on a day to day basis, a US official said Monday.

State Department spokeswoman Jen Psaki would neither confirm nor deny reports that a former US ambassador to Israel, Martin Indyk, has been chosen to head up the US negotiating team.

In Amman on Friday -- at the end of his sixth trip to the region -- Kerry announced that Israeli and Palestinian leaders have agreed in principle to return to talks frozen for three years.

Israeli chief negotiator Tzipi Livni and her Palestinian counterpart Saeb Erakat are due to travel to Washington within the coming days to start the talks.

"This is the first time in years the official negotiators for both sides have publicly agreed to meet at this level," Psaki told reporters.

But she could not give a precise date for the resumption of talks, saying US officials had been "in touch with both parties over the course of the last couple of days, but I don't have an update on the logistics of the date yet."

"Right now we are pursuing the way forward. There has been a great deal of work, compromise and sacrifice leading to this point," Psaki said.

But she stressed she was going to respect Kerry's commitment to keep the details of the negotiations secret in order to give them the best chance of succeeding.

The top US diplomat was now "focused on putting together the right combination of players to work with the parties," she said.

"We do expect, of course, to have a senior team in place, but no decision on a negotiator or envoy has been made."

Psaki said the talks are "going to be a challenging process. (Kerry) can't carry it all on his own shoulders day in and day out. And that's why he's looking to put together a senior team."

The State Department spokeswoman also stressed that both Israelis and Palestinians "have made clear they want to have substantive discussions as early as possible."

It's likely, however, that the agenda and process will be discussed first before the two sides try to get down to the thorny details on which they remain deeply divided.

White House spokesman Jay Carney hinted that it may take even longer for the talks to resume, telling reporters: "We are working on a date for the parties to come to Washington in the coming weeks."

He said the US administration felt "very cautious optimism" about the upcoming talks, stressing that the only way "to resolve these issues is if the two parties sit down in direct face-to-face negotiations."

Indyk, currently the head of foreign policy at the Brookings Institution, is a veteran of Middle East diplomacy and was named by several US media outlets as Kerry's choice to head the US team.

Indyk was assistant secretary of state for Near Eastern affairs under then president Bill Clinton and served as ambassador to Israel from 1995 to 1997.

He then again served as ambassador to Israel from 2000 to 2001. Indyk was born in London, but emigrated to Australia as a child. He became a US citizen in 1993.

"Obviously he's a very well-respected professional with a great deal of experience and background," Psaki said when asked about Indyk's qualifications.

"But I don't have any other updates on the personnel process," she insisted.