Israel has begun the process of releasing 26 Palestinian prisoners ahead of renewed Middle East negotiations.

Buses carrying the inmates, most of whom were held for attacks on Israeli citizens, left Ayalon prison in the center of the country late on Tuesday.

Israelis and Palestinians are set to launch talks in Jerusalem on Wednesday, following a preparatory round two weeks ago in Washington.

The prisoner release is part of an agreement to restart the talks after a five-year freeze.

The 26 inmates are the first of a total of 104 that Israel has promised to free within a year as part of a deal secured after months of shuttle diplomacy by US Secretary of State John Kerry, who has visited the region six times since March.

But Palestinian rights groups say that, upon close inspection, the deal is not the concession the Israelis are touting it to be.

Most of the detainees slated to be released on Tuesday have already served 20 years behind bars.

Al Jazeera’s Sue Turton, reporting from Ramallah, said some of the prisoners had written to Palestinian President Mahmoud Abbas and said that they did not want to be used as a bargaining chip in the talks.

Disdain for the Palestinian prisoners is strong in Israel, where media have featured detailed accounts of their alleged attacks on Israelis since a release roster was published two days ago. Palestinians, however, regard the men as heroes in a struggle for liberation.

A small gathering of Israelis demonstrated outside the prison during the release. The protesters included family members of Israeli prisoners calling for the release of their relatives rather than the Palestinian inmates.

Meanwhile on Tuesday, Kerry called the Israeli prime minister to discuss settlement approvals Israel had announced earlier in the day. Palestinian officials have said that these announcements “threatened” talks with Israel.

Israel approved more than 900 new illegal settlement units near the Palestinian town of Beit Jala in occupied East Jerusalem, in addition to 1,200 settlement homes approved two days ago.

“At the end of the day, I think people realize that the prisoners were detained precisely because they wanted to stop Israeli control over Palestine,” said Marwan Bishara, Al Jazeera’s senior political analyst.

“So it’s ironic that they are releasing [the prisoners] while they continue settlements.”

(Agencies and Al Jazeera – www.aljazeera.com)