It is part of a campaign of protest leading up to the planned visit to Israel and Gaza of United States President Bill Clinton in a week's time.

The BBC's Jeremy Bowen: "2400 prisoners have now stopped eating"

The hunger strikers say that as part of the peace process Israel should release prisoners who are being held for political activities against Israel or political violence, including murder.

More prisoners joined the campaign on Sunday, bringing the total to 2,400.

"They have launched an unlimited hunger strike in a bid to leave the prisons where they continue to languish five years after the signing of the Oslo accords with Israel," said Palestinian Prisoner Affairs Minister Hisham Abdelrazek.

Families of the hunger strikers are also demonstrating

He said the prisoners have stopped eating solid food but are allowing themselves to drink water. Hundreds of prisoners held in Israeli army camps have also stopped eating.

The Union of Palestinian Prisoners, based in Gaza, has called on the population to unite with the hunger strikers by staging their own protests.

Over the past few days there have been widespread demonstrations across the Palestinian territories to demand the release of the prisoners.

On Saturday, protests in several West Bank towns turned into violent clashes with Israeli troops, which left around 25 people injured.

Israeli spokesman David Bar-Illan: "We are not going to release anyone with blood on their hands"

Israeli troops fired tear gas and Palestinian officers fired rubber bullets as rioters threw stones and set fire to American flags.

The hunger strike campaign started nearly two weeks ago when around 100 Palestinian prisoners in Megiddo military prison in northern Israel stopped eating.

Troubled peace

President Clinton's visit to the region is a bid to shore up the troubled Wye River peace accord.

During negotiations for the interim agreement, Israel said it would release 750 Palestinians.

However, so far it has freed mainly petty thieves, not the political prisoners Israel regards as terrorists, but Palestinians believe are heroes.

The Israelis have said they will not release prisoners who, they say, "have blood on their hands".