Thousands of people have taken to the streets in Gaza venting their anger at Palestinian negotiators for offering big concessions in peace talks. Meanwhile, Tony Blair accused those behind this week's leak of documents of wanting to inflict serious damage on the peace process.

About 3,000 joined a rally organised by Hamas in support of anti-government protests in Egypt. But speeches and the shouts of the crowd focused on the leaked Palestinian papers and fierce criticism of the Palestinian Authority in Ramallah.

Thousands of pages of Palestinian documents covering more than a decade of negotiations with Israel and the US were obtained by al-Jazeera TV and shared exclusively with the Guardian.

The papers revealed that Palestinian negotiators were willing to go much further in offering concessions than their people realised.

In Gaza City the crowd of mostly young men chanted slogans against Fatah, the party that dominates the authority and is Hamas's bitter rival. "The concept of Palestine is not for sale," they shouted, before vowing loyalty to Hamas and promising never to relinquish Palestine's claims to its land and holy sites.

Mahmoud Saleen, 21, said: "We are here to deliver a message to the Palestinian Authority that they must come back to Palestinian ideas and reject the policies of American and Israel.

"We are against the political arrests in Ramallah and against the security coordination between Israel and the Palestinian Authority."

Yusef Salam, 20, said the leaders of the authority "are not from our own blood, they belong to the enemy more than they do to us. We hope there will be a revolution in the West Bank to relieve the Palestinian people from the people in power now."

Blair, the envoy of the Middle East peace quartet, said the release of the confidential documents prepared by Palestinian negotiators had been "destabilising". In an interview on BBC Radio 4's Today programme he urged the Palestinians to ignore the damage and press ahead with the drive for peace.

Asked how much damage the leaks had caused, Blair told Today: "I think it's hard to tell right now, but its intention was to be extremely damaging."

"I think we've just got to be big enough and strong enough to say, OK, whatever al-Jazeera are putting out, we're going to get on with making peace."