More than 50 Palestinians were killed and thousands wounded as Gazans clashed with IDF forces all along the Gaza-Israel border fence on Monday.

It was the highest Palestinian death toll in the Gaza Strip by Israeli fire since Operation Protective Edge in 2014.

The Hamas-run Health Ministry said 58 Palestinians were killed by IDF fire, including several teenagers, and 2,771 others were wounded, many by tear gas, with 116 in serious or critical condition.

Gazans have been protesting along the border with Israel for the past six weeks as part of what organizers have called the “Great March of Return.” But the mass protests on Monday were “unprecedented,” according to IDF Spokesman Brig.-Gen. Ronen Manelis.

According to the army, the violence began at 11:30 a.m. with hundreds of rioters running towards the fence in the northern part of the Strip. A number of Palestinians climbed the fence at several points.

Some 40,000 Palestinians took part in violent demonstrations at 13 different locations along the fence, throwing stones, explosive devices and Molotov cocktails at the fence and IDF troops, as well as burning tires and launching burning objects such as kites with charcoal or containers of burning fuel with the intention of setting fires in Israeli fields, the IDF said.

There were 25 kites flown over the course of the day, 17 of which had incendiary materials, causing 23 to set fire to a field before being extinguished by firefighting teams deployed to the area. More than 4,000 dunams of agricultural fields have been burned by such devices in the past month, an official from the Keren Kayemeth LeIsrael-Jewish National Fund told The Jerusalem Post.

Early on Monday, an IDF quadcopter, a drone with four rotors, was shot down near Jabaliya, in the northern Gaza Strip, leading the IDF to fire gas grenades and warning shots at protesters.

Amnesty International said the IDF response was deplorable.

“This is another horrific example of the Israeli military using excessive force and live ammunition in a totally deplorable way,” said Philip Luther, its research and advocacy director for the Middle East and North Africa. “This is a violation of international standards, in some instances committing what appear to be willful killings constituting war crimes.”

UN High Commissioner for Human Rights Zeid Ra’ad al-Hussein took to Twitter to condemn the “shocking” deaths, writing that “those responsible for outrageous human rights violations must be held to account. The international community needs to ensure justice for victims.”

The UN Security Council is expected to convene an emergency meeting on Tuesday over the violence following a request by Kuwait.

“The policy of Israeli authorities to fire irrespective of whether there is an immediate threat to life on Palestinian demonstrators in Gaza, caged in for a decade and under occupation for a half century, has resulted in a bloodbath that anyone could have foreseen,” said Sarah Leah Whitson, executive director of Human Rights Watch’s Middle East division.

According to the IDF, while the number of protesters was higher than in previous weeks, “it wasn’t as high as Hamas had hoped for, which is why the organization raised its level of violence.”

“Hamas placed many women at the front in an effort to make it difficult for us to deal with terror targets. This is the most significant level of violence we have seen since the start of the protests,” the IDF said, adding that despite intelligence that Hamas planned to breach the border fence en masse, that had yet to happen.

Hadashot TV news quoted Israeli security officials as warning Hamas via Egypt that if there were violent clashes along the border, Israel would resume the targeted killing of the group’s leaders, saying: “If the protests continue, the assassinations will return.”

Soldiers, including snipers, used tear gas and live fire to keep the thousands of protesters away from the fence. Intense gunfire was heard a few times close to areas where Gazans were demonstrating.

In response to terrorist attacks, Israeli jets and other aircraft struck 11 Hamas targets on Monday, and IDF tanks also struck two terrorist positions in the northern and southern Gaza Strip.

Late Monday afternoon, IDF fighter jets struck five Hamas targets in a training camp in Jabaliya following two attempts to plant explosive devices on the border fence near Rafah and Khan Yunis and gunfire toward soldiers near Jabaliya.

“The IDF will not allow damage to the infrastructure of the security fence and will act in a determined manner to defend and secure the citizens of Israel and its sovereignty,” the IDF said in a statement.

IDF Chief of the General Staff Lt.-Gen. Gadi Eizenkot held a situational assessment with Southern Command Commander Maj.-Gen. Eyal Zamir, Gaza Division Commander Brig.-Gen. Yehuda Fuchs and other commanders regarding the army’s ongoing operational activity.

Thousands of soldiers from 11 battalions, including from the Nahal and Givati brigades, special forces, intelligence-gathering units, the Armored Corps and snipers, and drones have been deployed to reinforce the troops already in the area. The training of regular combat troops has been put on hold to focus on the violent disturbances.

The IDF accuses Hamas of using the protests as cover to carry out terrorist attacks. On Sunday, its said it had identified protesters’ intentions to burn engineering tools belonging to the army, damage security infrastructures on the fence, including pillboxes, as well as attempts to kidnap soldiers under the guise of the protests.

Prime Minister Benjamin Netanyahu addressed the violence saying that “every nation has the right to defend its borders. Hamas clearly says its intentions are to destroy Israel and sends thousands to break through the border for that end. We will continue to act with resolve to defend our sovereignty and our citizens.”