US Secretary of State John Kerry on Tuesday held a second round of talks with Israeli Prime Minister Benjamin Netanyahu amid a push to salvage faltering peace efforts.

The breakfast meeting came after Kerry made a surprise trip to Israel to keep the talks on track amid a bitter tussle over the expected release of Palestinian prisoners.

There was no word of any breakthrough in efforts to keep the negotiations alive.

Although Kerry was scheduled to leave for a NATO meeting in Brussels on Tuesday morning, a senior Palestinian source said he would return to the region within 24 hours for talks with Palestinian Authority President Mahmoud Abbas.”Kerry will fly to Europe today for previous engagements and will come back to meet the president tomorrow at noon,” the Palestinian source told AFP.

Talks with Abbas were canceled Monday when a meeting with Netanyahu dragged on too late. Kerry met instead with the chief Palestinian negotiator Saeb Erekat and Palestinian intelligence chief Majid Faraj.

The two presented Kerry with Ramallah’s demands in exchange for agreeing to extend talks until the end of the year, including the release of nearly a thousand Palestinian prisoners, according to reports in Arab media. The identity of the prisoners would be partly decided by Israel and partly by the Palestinian authority.

Israeli has already agreed to release 400 more prisoners, officials told the Times of Israel over the weekend. However, the Palestinians are also seeking a settlement freeze and an Israeli commitment to not operate in areas of the West Bank under PA control, according to the reports.

Officials said a settlement construction moratorium would last eight months and not include East Jerusalem, Haaretz reported. The freeze would be de facto and not involve a formal moratorium.

The Palestinians are also seeking the release of a fourth batch of prisoners, already agreed to by Israel as part of the original deal to begin the current series of talks. The group of long-serving Palestinian prisoners was to have been freed over the weekend.

Sources close to the talks have revealed that the US is discussing the release of US-born Israeli spy Jonathan Pollard as a way to unblock the talks impasse, and coax Israel into agreeing to the releases and freeze on settlement building.

Pollard was arrested in Washington in 1985 and condemned to life imprisonment for spying on the United States on behalf of Israel. One proposal could see Pollard freed before the week-long Jewish holiday of Passover, which begins in mid-April.

In exchange, Israel would release the final batch of prisoners as well as another group of detainees, and the sides would agree to extend the talks.

State Department spokeswoman Jen Psaki however refused to be drawn, saying: “Jonathan Pollard was convicted of espionage and is serving his sentence. I do not have any update for you on his status.”

A number of Israeli officials have said the release of the prisoners would be too high a price to pay for Pollard’s freedom.

Deputy Defense Minister Danny Danon told Israel Radio Tuesday he would quit the government if Israel went ahead with the deal, even with Pollard thrown in.

The Palestinians on Monday gave Kerry a 24-hour deadline to come up with a solution to the row over the release of the Palestinian prisoners, or threatened to go to UN bodies later in the day to press their claims for statehood.

Erekat said the PA would not discuss extending talks until the fourth group of inmates — including several Israeli citizens — was released, according to Haaretz.

Jerusalem has not given any indication if it is still considering the release, which could bring down Netanyahu’s government.

US officials insist things are moving, saying only that there are a lot of complex pieces to put in place.

It appears that Kerry is shifting his focus away from reaching a framework, towards simply keeping the two sides talking after an April 29 deadline expires.

More meetings with Israeli officials were planned Tuesday, before Kerry was due to fly to Brussels to take part in NATO talks set to be dominated by Ukraine.

Avi Issacharoff contributed to this report.