GAZA CITY, Gaza Strip — Tens of thousands of Palestinians gathered Saturday at rallying points near the Israeli border to mark the first anniversary of weekly protests in the Gaza Strip.

Troops fired tear gas across the border and the Israeli military said some of the estimated 30,000 demonstrators threw rocks, grenades and burning tires towards them.

Palestinian activists clad in bright orange vests tried to keep people back, though some made it to the fence.

The army said it was responding with "riot dispersal means and firing in accordance with standard operating procedures."

Three Palestinians were killed during the demonstrations and hundreds more were injured, according to the Gaza Ministry of Health. Gaza medics said that a Palestinian teenager was killed by Israeli fire during the protests and that another Palestinian man was killed by Israeli fire before dawn on Saturday near the boundary. The identity of the third person was unclear.

More than 300 people were injured in the protest, according to the Gaza Ministry of Health, including at least four people who were in critical condition.

Confrontations have mounted this week ahead of the commemoration of the 'Great March of Return' protests, which began on March 30 2018. A Gaza rocket attack wounded seven Israelis north of Tel Aviv on Monday and, in response, Israel launched a wave of air strikes and ramped up its forces at the border.

The timing of the anniversary rally is sensitive for both sides.

Israeli Prime Minister Benjamin Netanyahu is seeking his fourth consecutive term in April 9 elections, but is facing a serious challenge from a group of ex-army chiefs who have criticized what they say is his failed Gaza policy.

In the final stretch of the campaign, Netanyahu needs to keep the Israel-Gaza frontier quiet, without seeming to make concessions to the Islamic militant Hamas.

Hamas, meanwhile, faces growing unrest in Gaza, as a result of worsening conditions after more than a decade of border closures. The fence protests, which began a year ago, were meant to break the blockade, but haven't delivered major improvements.

Early Saturday, Mohammed Saad, 21, was killed by Israeli army fire east of Gaza City near the perimeter fence, Gaza's Health Ministry said. It said he was hit by shrapnel in the head.

An Israeli army spokesman said about 200 Palestinians "rioted during the night along the fence" and that the army used riot dispersal means against them. He did not elaborate and had no comment about Saad's case.

A Gaza hospital worker, speaking on condition of anonymity because he was not authorized to brief the media, said Saad was a member of the so-called "night disturbance unit." Such groups routinely burn tires, flash laser lights and detonate explosives near the fence at night to distract soldiers and disturb residents of nearby Israeli communities.

The marches near the fence began a year ago, initially organized by grassroots activists. Hamas quickly took the lead, but a steady large turnout was also driven by widespread despair in Gaza.

The border blockade, imposed by Israel and Egypt after Hamas seized Gaza in 2007, has devastated Gaza's economy. Ground water has become undrinkable, electricity has turned into an intermittent luxury and the U.N. has warned Gaza will soon become uninhabitable.

The border marches routinely ended in confrontations, with some of the Palestinian demonstrators burning tires, hurling fire bombs or setting off explosives and Israeli troops firing live rounds and tear gas.

According to a Gaza rights group and a count by The Associated Press, 196 Palestinians were killed in the demonstrations over the past year, including 41 minors, and thousands were wounded by live fire. An Israeli soldier was also killed in the context of the marches.

Egypt has repeatedly tried to broker a cease-fire between Israel and Hamas, stepping up efforts in recent days after a Gaza rocket struck a house in central Israel earlier this week, injuring seven Israelis and threatening renewed escalation.

Palestinians with knowledge of the talks have said that as part of the proposed deal, Gaza protesters were to keep away from the fence Saturday and Israeli troops were to hold their fire.

Under the Egyptian plan, Israel was to offer economic incentives for Gaza in exchange for calm, according to Palestinian officials.

Earlier this month, Hamas quelled what have been portrayed as the fiercest protests yet against its mismanagement and failure to improve the internal economic situation.

Hamas blames the blockade and punitive measures by its West Bank-based rival, the Palestinian Authority, for worsening the living conditions.