The second stage of an "Israel"-Hamas prisoner swap is underway, as 550 Palestinian prisoners slated to be released were taken in buses from a jail in central Israel to crossing points into Palestinian territory and Jordan.

The prisoners are scheduled to begin crossing over at 2000 GMT.

Modest preparations were underway in Ramallah in the central West Bank, where the vast majority of the prisoners were to be dropped off, and in Gaza, the home of 41 of the 550.

Two others, from Jordan, were to cross the border with Israel's eastern neighbour via the Allenby Bridge over the River Jordan. Two others were from East Jerusalem.

Hours before the release got underway, hundreds of Palestinian clashed with Israeli soldiers at a central West Bank checkpoint. They were among the crowd gathered at Beitunia, south-west of Ramallah, anxiously awaiting their relatives who are being freed.

Tempers ran high and, when youths began pushing the nearby security fence and throwing rocks, soldiers fired tear gas and stun grenades, witnesses said. An Israeli military spokeswoman said some of the protesters also threw firebombs.

Sunday's release will complete an Egyptian-brokered deal to exchange a total of 1,027 prisoners for Gilad Shalit, who was captured by Gaza fighters in June 2006. Schalit returned home on October 18 when Israel freed the first batch of 477 prisoners.

Al Jazeera's Cal Perry, reporting from Ramallah where thousands had gathered to greet the prisoners, pointed out that Sunday's group is "very unlike" the first round of released prisoners.

"That batch was released after very, very difficult negotiations [with Hamas]. This was a list picked by the Israelis," said Perry.

The prisoners that Israel freed in the first round included dozens of fighters serving life sentences for involvement in deadly attacks. Their releases set off ecstatic celebration in the Palestinian territories, particularly Hamas' Gaza stronghold.

In Gaza, Hamas spokesman Fawzi Barhoum said the movement welcomed the release of all prisoners, regardless of their political affiliation.

"We are proud of this great achievement," he said.

He said Hamas leaders would welcome all returning prisoners, and offer them assistance with housing, employment and finding a spouse.

Al Jazeera's Perry said both Hamas and "Israel" are capitalizing on the high-profile nature of the Shalit trade to "play a public relations game".

"Both sides are still trying to work this to their favor politically," he said.

After the release, some 4,250 Palestinians will remain in Israeli prisons for security-related offences, the "Israel" Prison Service said.

That is down from almost 5,300 before the Shalit deal, although new arrests have since been made, and others have been released.

Al-Jazeera/AB