Clashes have broken out between Palestinian protesters and Israeli security forces at the Qalandiya checkpoint on the outskirts of Jerusalem amid 'Land Day' demonstrations.
At least 121 people have been injured in clashes at the checkpoint, mostly from tear gas, according to medical sources and Al Jazeera's correspondents in Qalandiya.
Four medical workers were reported to have been shot with rubber coated bullets and one car was set ablaze.
Al Jazeera's Cal Perry reported that Israeli security forces tried to push hundreds of protesters back toward the nearby West Bank town of Ramallah, using water cannon and tear gas. Rocks were thrown, tires set alight and Red Crescent ambulances could be seen at the scene.
"This is a place where we frequently see clashes, and what we're seeing here is the Israeli army needing to put a barrier up and not let people through," our correspondent said.
"These clashes seem to be a bit more fierce today, and have started earlier in the day than usual."
Perry said hundreds of Israeli police had been deployed in occupied East Jerusalem and high levels of security were in place across the city.
Mustafa Barghouti, a Palestinian organiser, said that activists from 82 countries were expected to participate in Land Day activities, which commemorate six Palestinian-Israelis killed by Israeli security forces in 1976 during protests over the confiscation of their land.
Mahmoud Aloul, a Palestinian leader in the occupied West Bank involved in preparations there, said demonstrations were also underway in Bethlehem, where at least six people were reported injured.
Other events were held in the northern West Bank city of Nablus, were at least three people were said to have been wounded in clashes with the Israeli border police, medical sources told Al Jazeera.
Activists in Gaza planned to hold a demonstration about a kilometre from the Israeli border, but said they did not plan to move closer to minimise the chance of clashes.
Supporters in neighbouring countries also planned marches near the Israeli borders in a solidarity event dubbed a "Global March to Jerusalem".
Israel on Thursday announced a general closure of the West Bank from late on Thursday until late on Friday "in accordance with security assessments", while authorities have deployed thousands of troops and police across the country and along its borders.
Yohanan Danino, the Israeli police chief, raised the nationwide level of alert "in order to handle any possible scenario, expected or not".
Police were also expected to impose an age limit on worshippers attending the weekly Friday prayers at the Al-Aqsa mosque compound in Jerusalem's old city.
In a statement to mark the day, Palestinian negotiator Saeb Erakat said Israel's policy of denying access to land was "at the heart of the conflict”.
Palestinians had a right to demonstrate peacefully and to demand "the fulfillment of their national and legal rights", he said.
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