MUNICH, Germany — Prime Minister David Cameron, in a speech attended by world leaders, on Saturday criticized his country’s longstanding policy of multiculturalism, saying it was an outright failure and partly to blame for fostering Islamist extremism.

He said the U.K. needs a stronger national identity to prevent people turning to extremism.

"If we are to defeat this threat, I believe it's time to turn the page on the failed policies of the past," he told an international conference in Munich.

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“Under the doctrine of state multiculturalism, we have encouraged different cultures to live separate lives, apart from each other and the mainstream,” Cameron said during a panel discussion attended by German Chancellor Angela Merkel. “We have failed to provide a vision of society to which they feel they want to belong.”

He said the “hands-off tolerance” in Britain and other European nations has encouraged Muslims and other immigrant groups “to live separate lives, apart from each other and the mainstream.”

Muslim groups in the U.K. quickly condemned the remarks. Among them was the Muslim Council of Britain, which receives government money for projects intended to combat extremism. The council said that the Muslim community was still being treated "as part of the problem as opposed to part of the solution."

Many also criticized the timing of the speech, which took place on the day that members of the far-right English Defence League (EDL) held a rally in the ethnically mixed city of Luton to protest the spread of Islam in Britain.

Cameron did not mention the EDL, but a lawmaker for the opposition Labour Party, Sadiq Khan, accused him of "writing propaganda for the EDL," AFP reported.

Cameron’s remarks echoed statements made last year by Merkel last year, when she also called multiculturalism a failure.