JERUSALEM  - Israel on Saturday announced it will release some Palestinian prisoners as a "gesture", after the two sides agreed to lay the groundwork to resume peace negotiations frozen for three years.

Some of those to be released have been held in Israeli prisons for decades, Israeli Intelligence Minister Yuval Steinitz told public radio. His announcement came hours after US Secretary of State John Kerry said on Friday that Israeli and Palestinian negotiators had agreed to meet to pave the way for a resumption of direct peace talks. The last round of direct talks broke down in 2010 over the issue of Israeli settlements in the West Bank and east Jerusalem.

Steinitz said on Saturday his government would engage in the staged release of a "limited number" of prisoners, some of whom he defined as "heavyweights", who have been in jail for periods of up to 30 years. "There will definitely be a certain gesture here", he said without noting the number of prisoners to be freed.

According to a recent assessment by Israeli rights group B'Tselem, at least 4,713 Palestinians are imprisoned in Israel.

Their release is one of the Palestinians' key demands for resuming peace talks, particularly the 107 prisoners arrested prior to 1993, when the Oslo peace accords were signed.

An Israeli official said no prisoners would be released before direct talks begin and the process would then be dependent on the Palestinians proving they are "really serious and not playing games."

"It won't happen tomorrow and not next week", the official told AFP, speaking on condition of anonymity. He could give no idea of the number of prisoners involved.

He said the releases, once they begin, would take place in stages and include "pre-Oslo prisoners, prisoners set to be released anyway, and those the Palestinians 'forgot' during the Oslo accords".

Minister Steinitz stressed that Israel would not be compromising on "diplomatic issues", and that there was no agreement on a settlement construction freeze or on accepting the borders that existed prior to 1967 Six-Day war as the basis for talks, as demanded by the Palestinians. He said for their part the Palestinians had committed to "negotiate seriously" for "at least nine months," during which they would refrain from action at the United Nation and other international institutions.

Kerry gave away very little detail of the agreement, which came after he spent four days consulting the Israeli and Palestinian leadership.

Just minutes before boarding a plane to fly home from Jordan, Kerry told reporters both sides had reached "an agreement that establishes a basis for resuming direct final status negotiations".

"This is a significant and welcome step forward," he added, having doggedly pushed the two sides to agree to resume talks in six intense trips to the region since becoming the top US diplomat in February.

A US State Department official said Kerry had wrenched a commitment from both sides "on the core elements that will allow direct talks to begin".

The Israelis and Palestinians remain far apart on final status issues including the borders of a future Palestinian state, the right of return of Palestinian refugees, and the fate of Jerusalem which both want as their capital.

Palestinian president Mahmud Abbas has also repeatedly called for a freeze to Israeli settlement building and a release of prisoners.

Analysts cautioned against reading too much into the latest developments.

Gal Berger, Palestinian affairs correspondent for Israel's public radio pointed to the fact that Yitzhak Molcho, the personal envoy of Prime Minister Benjamin Netanyahu, has already been holding talks with Erakat, which were still ongoing.

"Now Livni is being added, but it is still not a meeting at the level of the leaders (Netanyahu and Abbas)," he said.

Predictably, the Islamist Hamas movement which runs the Gaza Strip rejected a return to talks, its spokesman Sami Abu Zuhri saying Abbas had no legitimate right to negotiate on behalf of the Palestinian people.

And the leftist Popular Front for the Liberation of Palestine warned in a statement that "a return to talks outside the framework of the United Nations and its resolutions would be political suicide."