The Palestinian leadership will put to a referendum any deal reached in US-brokered talks with the Israelis on settling the historic conflict – matching a pledge made by the Israeli prime minister.

Amid continuing uncertainty about whether Palestinian negotiators have fully committed to beginning preliminary talks in Washington next week, the president, Mahmoud Abbas, said: "Any agreement reached with the Israelis will be brought to a referendum."

On Sunday Binyamin Netanyahu told the Israeli cabinet that any deal would be put to the public for endorsement. "I do not think that such decisions can be made, if indeed an agreement is achieved, by this or that coalition process; it must be put to the people for a decision," the Israeli prime minister said.

Israel has never held a referendum in its 65-year history and such a move would require legislation.

Opinion polls suggest a majority backing on both sides for a two-state solution to the conflict, but the details of any agreement will be crucial in determining the outcome of any plebiscites. There are also strong opponents of concessions on both sides; notably, Israelis settlers and their supporters, and Hamas in Gaza.

Abbas made his referendum pledge in an interview with a Jordanian paper, Al Rai, in which he also said: "The United States is serious in formulating a solution to the Palestinian issue, through introducing a Palestinian state within the 1967 lines with East Jerusalem as its capital."

He added: "We want to reach a two-state solution … but as of now we have not achieved anything."

The Palestinians are wary of beginning preliminary talks with the Israelis without a firm assurance from the US secretary of state, John Kerry, that the pre-1967 border will be the basis of territorial negotiations.

In a statement on Sunday evening, Abbas's spokesman, Nabil Adu Rudeineh, said discussions over the parameters for talks were continuing. Abbas had agreed to send a delegate to Washington to continue thrashing out the terms for negotiations, he added.

A Palestinian source told the Guardian on Sunday that Kerry had written a letter giving a US assurance that the basis of territorial talks would be the pre-1967 border, but it was not clear whether the letter had been delivered.

"If we have well defined terms of reference and a clear timeframe – by which we mean the end of the year – we will go into talks," the source said.

More details about the release of Palestinian prisoners in Israeli jails – part of a pre-talks agreement – were reported in the Israeli media. Eighty-two long-term prisoners would be freed in four stages. The first releases would come after four to six weeks of talks, and the remaining prisoners would be released at similar intervals.

The Palestinians demanded the release of 103 prisoners who have been in jail since before the Oslo accords were signed almost 20 years ago.

Netanyahu is expected to seek approval from his cabinet or security cabinet of the prisoner release amid opposition from some government ministers and members of parliament.