Police had to accompany Jewish students from a lecture hall at a London university after they were trapped by anti-Israel protesters.
One student claimed she had been "assaulted" while attending the talk by Hen Mazzig, an Israeli speaker, at University College London last night.
Officers entered the room and carried out an evacuation of members of UCL’s Friends of Israel group amid chaotic scenes.
Demonstrators had entered the room to fly Palestinian flags and chant. The event was being live-streamed online and the disruption was clear on the video footage, with protesters banging on windows and screaming "Palestine! Palestine!".
The event was run by the UCL Friends group and King’s College London’s Israel Society.
Devora Khafi, a volunteer with the StandWithUs advocacy group, tweeted: “I was assaulted. We were attacked. But freedom will prevail. @HenMazzig did a great job sharing his story amidst a whirlwind of hate.”
Mr Mazzig served in the IDF for five years as an openly gay commander. He is a former lieutenant who worked as an intermediary between the IDF and the Palestinian Authority, United Nations and other groups in the West Bank.
Shortly after being taken out of the room at around 9pm, he tweeted:
I had to be rushed out of the event at @UCL with security. The campus was the war zone and the streets are the safe place. I'm out. My god.
The Community Security Trust confirmed all the Jewish students had been safely helped from the room. Footage shows Jewish audience members being led from the building by police, as activists scream "shame, shame" at them.
Police confirmed officers remained at the venue until the meeting had "ended safely". An investigation has now begun into an allegation of common assault.
The JC understands the Board of Deputies has been involved in efforts to get UCL chiefs to investigate the incidents on their campus.
The Board is understood to have made four demands of UCL; for an immediate "rigorous" inquiry, for disciplinary action against UCL staff and students involved in the incident, for a statement giving assurances that Jewish students are safe on the campus, and for a meeting with the UCL Provost.
UCL issued a statement in which it said "we did all we could" to ensure the event went ahead as planned by the Friends of Israel group.
It added: "UCL and UCLU do not condone acts of intimidation or violence under any circumstances and, as a university with a longstanding radical history, we fiercely support the right to exercise free speech within the law.
"The freedom to debate and challenge views is fundamental to the nature of a university. We also acknowledge the right to peaceful protest.
"We did all we could to ensure that the UCLU Friends of Israel Society event could go ahead at UCL, working with our security team and the Metropolitan Police.
"It was widely advertised and open to the public, and as result a small but noisy group of protesters attended and occupied the rooms where the event was originally meant to take place.
"UCL security found an alternative location and ensured the event went ahead safely. We regret protesters took measures to try to prevent the event from happening but stress that the protest was non-violent.
"We are aware that the Metropolitan Police attended following accusations of assault and support them fully in their investigations. As this was a public event, it is unclear how many UCL students were present but we are instigating an enquiry and will consider disciplinary action against any student where there is evidence that they may have breached our disciplinary regulations.
"Both UCL and UCLU have a code of practice governing the participation of external speakers at events held at UCL. It is clearly stated in UCL’s code of practice that the premises will not be denied to any individual on any ground connected with their beliefs. The code also requires speakers to behave lawfully and avoid any action or language which is offensive, provocative or a clear incitement to violence.”
The National Union of Students said it would not be commenting on the incident.
In a statement, the Union of Jewish Students said: “There can be no excuses for the events that took place at UCL last night.
“The fact that such violence and hostility took place only nine months after the incident at KCL, with police having to once again be called, is an absolute disgrace.
“UCL Friends of Israel were simply trying to engage students in discussion on Israel, but instead were met with a wall of intolerance and intimidation aimed at shutting down free speech.
“It is reassuring however that, despite the acts of the protestors, the event went ahead as planned with around 50 engaging in peaceful and positive discussion on Israel and Palestine.
“We would like to commend the organisers of last night's event for their commitment in ensuring the event went ahead as planned. Despite the hostility, Jewish and non-Jewish students alike, across the country, will never stop engaging in constructive debate around Israel/Palestine.
“It is imperative that UCL and UCLU take action following last night's events and we will be working with UCL Friends of Israel to ensure just that. Whatever your position on the Israeli-Palestinian conflict, there is no place for intolerance and intimidation like was seen last night at UCL on university campuses."
The Israeli embassy in London said: "We are concerned by the shameful violence recorded at last night’s event at UCL aimed at preventing an Israeli speaker from engaging students. We are confident the university will be investigating those responsible.”
In a statement the Board said: “We deplore the aggressive and intimidating protests which took place in @ucl against an Israeli speaker. Free speech was shut down.”
Sir Eric Pickles, Conservative Friends of Israel chair, said: "The shameful events of last night provide another sad insight into the levels of intimidation and harassment that Jewish and Israeli students can experience on university campuses across the UK.
"Having spoken just the day before at a UCL Holocaust remembrance conference held in a suitably respectful atmosphere, it was concerning to see the vastly different response to a pro-Israel event at the same university.
"The apparent antisemitism lurking behind some hard-line anti-Israel 'activists' is a terrible indictment of the intolerance of some modern students. Free speech must be guaranteed and protected for all."
UCL markets itself as a "global university" with a high proportion of international students. It is thought around 500 Jewish students attend the university.