At least 44 people have died in a crush at a Lag b’Omer gathering in the north-east of Israel.
Dozens more were injured at the festival, which takes place annually at the foot of Mount Meron, and is attended by thousands of Strictly Orthodox Jews.
It was the largest event in Israel since the coronavirus pandemic began.
Prime Minister Benjamin Netanyahu described it as a "heavy disaster" and said he was praying for the casualties.
Early reports suggested a structure at the site had collapsed, but later reports suggested that people had slipped on steps,starting a crush.
The Times of Israel reported the police force’s Northern District Commander Shimon Lavi, who oversaw the security arrangements at Meron, saying he bore "overall responsibility".
“I bear overall responsibility, for better or worse, and am ready for any investigation,” he told reporters.
Massive crowding ahead of Mt Meron tragedy; death toll up to 44 pic.twitter.com/ne9OqZnVD1
— Luke Tress (@luketress) April 30, 2021
But he stressed that the cause of the disaster was still unclear. Some eyewitnesses accused police of blocking a key exit.
There is an ongoing “complicated effort to gather evidence to reach the truth,” he said.
He also says that police officers saved lives during the stampede, pushing through the crowds to rescue those trapped.
The Justice Ministry meanwhile has said would open an investigation into possible police negligence.
The Abu Kabir Forensic Institute is set to receive the bodies of the stampede victims, ahead of the identification process, the Health Ministry says.
Statements of condolence have poured in from around the world, including the EU and the US National Security Adviser.
Our hearts go out to the people of Israel tonight following the terrible tragedy at Mount Meron. We offer our condolences to the families and friends who lost loved ones in this disaster, and wish a full and swift recovery to those injured.
— Jake Sullivan (@JakeSullivan46) April 30, 2021
The Board of Deputies said it was "devastated". President Marie van der Zyl said: "Lag BaOmer traditionally celebrates the cessation of death of religious students from a terrible plague in Roman times. It is a bitter irony that the day will now become partly known as a day of mourning for the families affected. Our thoughts and prayers are with the injured and with the families of the deceased. May the memories of the deceased be for a blessing.”
Chief Rabbi Pinchas Goldschmidt, president of the Conference of European Rabbis, said he was “in shock and mourning over the catastrophe in Meron during the Lag Ba’Omer celebrations. Our prayers are with the wounded and victim’s families.”