Medics and rescue workers attend to the Lag B'Omer event in Mount Meron, northern Israel, where fatalities were reported among the thousands of ultra-Orthodox Jews gathered at the tomb of a 2nd-century sage for annual commemorations that include all-night prayer and dance, at Mount Meron,

The disaster occurred in Meron at the site of the reputed tomb of Rabbi Shimon Bar Yochai, a second-century Talmudic sage, where mainly ultra-Orthodox Jews flock to mark the Lag BaOmer holiday

A massive stampede at a densely packed Jewish pilgrimage site killed 44 people in northern Israel on Friday, leaving emergency workers scrambling to clear the area and evacuate the critically injured.

Magen David Adom rescue service tweeted that it was treating 103 people, including 38 in critical condition. Israeli media had earlier reported that a grandstand collapsed, but the rescue service said all the injuries happened in a stampede.

The disaster occurred in Meron at the site of the reputed tomb of Rabbi Shimon Bar Yochai, a second-century Talmudic sage, where mainly ultra-Orthodox Jews flock to mark the Lag BaOmer holiday.

Closed last year due to coronavirus restrictions, this year's pilgrimage was the largest public gathering since the pandemic began.

Rescue workers had initially said that chaos erupted when a section of stadium seating collapsed but later revised that account to say the casualties had been caused by a stampede.

Israeli media published an image of a row of bodies covered in plastic bags on the ground.

The Magen David Adom, Israel's rescue service, reported dozens of dead and said it would "fight for the lives of dozens wounded, and will not give up until the last victim is evacuated."

Emergency services deployed six helicopters to evacuate the injured.

The army said its medical teams and "a number of Israeli Air Force helicopters with medical teams... are assisting in the mass casualty incident in Mount Meron."

"The forces are assisting in the evacuation of injured and killed civilians and providing medical treatment at the scene," it added.

"This is one of the worst tragedies that I have ever experienced," said Lazar Hyman of the United Hatzalah volunteer rescue service, who was at the scene.

"I have not seen anything like this since I entered into the field of emergency medicine," he added.

Yehuda Gottleib, one of the first responders from United Hatzalah, said he saw "dozens of people fall on top of one another during the collapse".

"A large number of them were crushed and lost consciousness."

Israel has fully vaccinated more than half of its 9.3 million population against coronavirus, but restrictions on massive public gatherings remain in place to stem the spread of the virus.

Authorities had authorised 10,000 people to gather at the site of the tomb but organisers said more than 650 buses had been chartered from across the country, bringing 30,000 pilgrims to Meron.

The Meron pilgrimage is primarily attended by ultra-Orthodox Jews, a community that has at times resisted mandatory health and safety measures during the pandemic.

Around 5,000 police had been deployed to secure the event. The area has since been closed, with rescue workers and security forces attempting to clear the area.