By Ivana Kottasová, Lauren Iszo, Dana Karni, Sarah Sirgany and Eugenia Yosef, CNN

(CNN) — Four Israeli soldiers have been killed and more than 60 people injured in a Hezbollah drone attack on an army base in central-northern Israel, according to first responders and the Israeli military.

The incident late Sunday local time is one of the bloodiest attacks on Israel since the beginning of the war last October.

The Israel Defense Forces (IDF) said an unmanned aerial vehicle, or UAV, launched by Hezbollah hit an army base adjacent to Binyamina, a town north of Tel Aviv that lies some 40 miles from the Lebanese border.

The four killed soldiers were all 19 years old and in infantry training at the base, the IDF said, adding that eight other soldiers were severely injured.

According to Israel’s Magen David Adom emergency service, a total of 61 people were wounded in the attack, with dozens still hospitalized.

The news comes after Hezbollah said Sunday it had fired a swarm of attack drones on an Israeli infantry training camp in Binyamina.

The Lebanon-based militant group said the attack was in response to deadly Israeli strikes in Lebanon Thursday.

Hezbollah said it had targeted the Golani Brigade, an infantry unit of the Israel Defense Forces (IDF) that has been deployed in southern Lebanon. The claim of responsibility for the attack came shortly after the militant group released an audio message from its slain leader Hassan Nasrallah calling on its members to “defend your people, your family, your nation, your values and your dignity.”

Earlier on Sunday, the IDF said it had intercepted a Lebanon-launched UAV without specifying where. It was not immediately clear whether this was the same incident that led to the injuries.

Israeli air defence systems tend to be very reliable, but on Sunday, there were no reports of alerts in the Binyamina area at the time of the attack, raising questions of how the drone was able to penetrate so deep into the Israeli territory without being spotted.

Hezbollah said it had fired dozens of rockets toward the northern Israeli towns of Nahariya and Acre to engage Israel’s air defense systems, while simultaneously launching the drone swarm.

“These drones broke through the Israel defense radars without detection and reached its target at the training camp of the elite Golani Brigade in Binyamina,” Hezbollah said.

The IDF’s top spokesperson Rear Adm. Daniel Hagari said the military would investigate how the drone got through without raising an alarm at the base.

“We will learn from and investigate the incident,” he said in a video statement from the base. “The threat of UAVs is a threat we are dealing with since the beginning of the war. We need an improvement to our defense,” he added.

‘Very difficult scene’

The Binyamina attack comes almost two weeks after Israel launched a ground operation in southern Lebanon. The IDF has insisted the operation is “localized” and “limited” – even though the reality on the ground suggests it might be preparing for a wider invasion.

The IDF has issued evacuation orders for a quarter of Lebanon’s territory and deployed units from four different IDF divisions to the border area, while also continuing an intense bombardment campaign.

More than 1,500 people have been killed and more than 8,000 injured in Lebanon since September 16, when Israel stepped up its campaign against Hezbollah, according to a CNN tally of Lebanese health ministry statements.

Tensions rose again on Sunday after Israeli Prime Minister Benjamin Netanyahu called on the United Nations peacekeeping forces in southern Lebanon to withdraw from the area following several incidents involving the IDF that left five members of the UN Interim Force in Lebanon (UNIFIL) injured.

The 40 countries whose soldiers serve as UN peacekeepers in Lebanon issued a statement on Sunday “strongly condemning” these attacks.

At the same time, Israeli Defense Minister Yoav Gallant said Israel would not allow Hezbollah to return to border villages in southern Lebanon after Israeli troops leave the area.

Despite the ground operation targeting its infrastructure, Hezbollah continues to fire dozens of rockets into Israel on daily basis.

The attack on Sunday also raises concerns over Hezbollah’s ability to use longer-range drones against Israel, as it comes just two days after another attack in which the IDF said two drones were launched from Lebanon.

The Israeli military said Friday it had intercepted one of those drones, but did not specify what happened to the other one. In the attack Friday, warning sirens had activated and while a nursing home in the coastal city of Herzliya, central Israel, was damaged, no casualties were no reported.

Magen David Adom said it declared a mass casualty event on Sunday evening and had evacuated 61 injured people from the scene. It said three people were in serious condition and 18 suffered moderate injuries.

A statement from the emergency service quoted a paramedic at the site as saying it “was a very difficult scene.”

“We declared it a mass casualty event and treated patients suffering from blast injuries and shrapnel. The injuries were severe, and we evacuated the injured to hospitals as quickly as possible for further medical treatment,” Rafi Sheva said in the statement.

Those injured in Binyamina were transported to eight different hospitals across Israel, according to Magen David Adom.

The Laniado Hospital in north-central Israel treated several of the people who suffered light injuries.

Its spokesperson Asahel Shahaf said that one man who was brought into the emergency room had a lucky escape when shrapnel from the drone lodged into his kippah, a head covering worn by Jewish men.

“The shrapnel did not scratch the wounded man,” Shahaf said, calling the incident “a small (big!!!) miracle.”