Clashes broke out outside the military court in the West Bank as demonstrators demanded the release of the activists.

Protesters had initially listened to speeches from leaders of the Palestinian Authority and Fatah. Then clashes broke out between the younger demonstrators and Israeli police, who fired tear gas at the protesters in an effort to force them away from the prison.

Politically significant

Palestinians view the detentions as politically significant, especially that of Zaki.

in depth

  Israel expands settlements
  Israelis protest freeze
  Map of East Jerusalem housing plan
  Comments: US-Israel relations
  Jerusalem's religious heart
  Strain on US-Israel ties
  Q&A: Jewish settlements
  Riz Khan:
  Middle East peace process
  Battle over settlements
  Inside Story:
  US and Israel poles apart
  Israel: Rise of the right
  Holy Land Grab

Zaki is the most senior ranking Fatah official to have been detained by Israel since the signing of the Oslo peace accords between Israel and the Palestinians in 1993.

On Sunday Zaki was participating in a rally against Israeli restrictions on Palestinian Christians.

There have been increasing incidences recently of Israel arresting Palestinian peace activists and deporting foreign activists.

"This, as far as the Palestinian leadership is concerned is an indication of where Israel wants to take things. And the response from the political leadership has been a commitment to step up popular resistance," our correspondent said.

"The message being is Israel is going to ban peaceful marches, what does it consider legitimate opposition to their occupation.

"The circumstances surrounding these arrests and the fact that the Palestinians are increasingly frustrated due to the crackdown on non-violent protest is ... being reflected in the rising political tensions between Israel and the Fatah movement, which is the champion, among Palestinians, of peace negotiations with Israel."