Israel's negotiating position with the Palestinians in US-sponsored peace talks is the toughest it has taken since before the 1993 Oslo Accords, a senior Palestinian official said on Tuesday.

"The current Israeli negotiating position is the worst in more than 20 years," said Yasser Abed Rabbo, a top official with the Palestine Liberation Organisation, adding there had been "no tangible progress" in talks that resumed in July after a hiatus of nearly three years.

"They want security first, and that the borders of the state of Palestine should be set out according to Israeli security needs that never end, and that will undermine the possibility of establishing a sovereign Palestinian state," Abed Rabbo, secretary general of the PLO executive committee, said in a statement.

Prime Minister Benjamin Netanyahu insists on an Israeli military presence in the Jordan Valley region of the occupied West Bank in any final settlement, although the Palestinians refuse to countenance troops on land they want for a future state.

US Secretary of State John Kerry, who in July nudged the Israelis and Palestinians into resuming talks frozen since September 2010, held a seven-hour meeting with Netanyahu in Rome last Wednesday.

On Monday, Kerry said that the Israeli-Palestinian talks, which take place under an American-imposed media blackout, have "intensified."

He said that since the end of July, 13 direct meetings had taken place.

"The pace has intensified, all the core issues are on the table and they have been meeting with increased intensity," Kerry said.

"It is no secret to anybody that this is and remains a difficult process, there is no shortage of passionate sceptics," he added.