A controversial former US Marine is being investigated by police following allegations that he incited racial hatred at an Israel Apartheid Week event.

Ken O'Keefe screamed at audience members, said Israel "must be destroyed" and claimed Mossad was "directly involved" in the September 11 terror attacks on the United States.

He told an audience at Middlesex University's Free Palestine Society: "If Israel is inherently a racist, apartheid state, then I want no part of it. Israel has no place in this world and it must, in its current form, if you want me to use some inflammatory language, be destroyed.

"The Jewish state is acting on behalf of the Jewish people. You [the Jewish people], like the Nazis, now have a special obligation. The decent Germans of World War Two, what did they do when the Nazis came to power and instituted their policies? Did they do enough to stop the Nazis? No, they didn't.

"What are the Jewish people doing right now? Are you doing enough to stop your racist, apartheid, genocidal state?"

Mr O'Keefe, who travelled on the Mavi Marmara ship as part of the flotilla to Gaza in 2010, appeared with Liberal Democrat peer Jenny Tonge and Palestinian author Ghada Karmi.

Baroness Tonge's resignation from the Lib Dems came after her refusal to apologise for anti-Israel comments made at this event.

There were heated scenes as Mr O'Keefe clashed with supporters of Israel following his comments, and organisers repeatedly threatened to throw out Zionist Federation co-vice-chairman Jonathan Hoffman.

Mr O'Keefe, who said his wife and children were Palestinian, also accused Ashkenazi Jews of running an apartheid regime in Israel against other Jews.

He said: "Ashkenazi Jews have no claim to this land at all, and that's a fact. They are the ones you find in all the high positions of power. The Sephardi Jews, who actually come from that region, are not in the same level at all. Never mind Ethiopian Jews and Jews from other parts of the world."

Challenged by Jewish audience members, he shouted: "I'm answering the question, shut your mouth."

Mr O'Keefe said Palestinians had been pushed to commit suicide bombings because of "extreme oppression" and claimed Mossad vehicles containing explosives had been found travelling to New York at the time of the 9/11 attacks.

"Israel and Mossad were directly involved in 9/11," he said. "Israel continues to spy on America and Britain and continues to falsify terrorism. The major tactic of the Zionists and their collaborators is slander and lies."

He described himself as a "warrior willing to die for Palestine" and denied allegations he was either an Al-Qaeda operative or a Mossad agent.

Following last Thursday's event, two pro-Israel activists in the audience reported Mr O'Keefe to police. A Barnet Police spokesman said: "Evidence from the event is being reviewed. This is obviously a delicate investigation that will require balancing the right to free speech, and the rights of people not to be discriminated against".