A march in which protesters chanted violent anti-Western slogans such as "7/7 is on its way" should have been banned, a leading British Muslim said.
Protesters waved placards outside London embassies on Friday
Asghar Bukhari said the demonstration in London on Friday should have been stopped by police because the group had been advocating violence.
The chairman of the Muslim Public Affairs Committee said the protesters "did not represent British Muslims".
More protests over cartoons of Muhammad on Saturday passed off peacefully.
Mr Bukhari told the BBC News website: "The placards and chants were disgraceful and disgusting, Muslims do not feel that way.
"I condemn them without reservation, these people are less representative of Muslims than the BNP are of the British people."
He said that Muslims were angry over satirical cartoons of the Prophet Muhammad published in European papers but it was "outrageous" for anyone to advocate extreme action or violence.
"We believe it [the protest] should have been banned and the march stopped.
"It's irrelevant whether it's Muslims causing hatred or anyone else - freedom of speech has to be responsible."
Police estimated Friday's crowd at between 500 and 700 and no arrests were made.
Protesters voiced their anger over the cartoons at the Danish embassy
On Saturday more protesters, organised by the Hizb ut-Tahrir group, gathering outside the Danish embassy in London.
It appeared that the rally was far more restrained than the one on Friday.
Police later said two men had been arrested near the embassy during the protest.
"They were arrested to prevent a breach of the peace, after a search by officers found leaflets including cartoons of the prophet Mohammed," a Met spokeswoman said.
The UN's Kofi Annan has urged Muslims to accept the apology from the paper where the cartoons first appeared.
Foreign Secretary Jack Straw has praised UK media for not publishing them.
Mr Straw said the decision by some European newspapers to print the cartoons was "disrespectful" and he added that freedom of speech did not mean an "open season" on religious taboos.
Flanked by a forest of messages such as, "'Freedom' to insult", a speaker at Saturday's rally told the crowd they were demanding an end to "vilification".
"If you want to debate and criticise then we are ready and we have been waiting, but we are not going to accept these images," he said.
He called on "the governments of the Muslim world to completely sever all contact with European governments" until they had "controlled the media".
Among the images which have sparked outcry is one of Muhammad with a bomb-shaped turban on his head. Newspapers in Spain, Italy, Germany and France reprinted the material.
They have sparked protests across the Middle East.
UK Muslims have denied that the reaction to the cartoons' reproduction has been a threat to freedom of speech.
Inayat Bunglawala, from the Muslim Council of Britain, told the BBC that any kind of cartoon that was derogatory to a race or group in a stereotypical way was "unacceptable".
"Of course Europe has the right to freedom of speech, and of course newspapers have the right to publish offensive cartoons. This was really a question about exercising good judgment," he said.
"Knowing full well the nature of these cartoons, they were offensive, deeply offensive to millions of Muslims, these newspaper editors should have exercised better judgment.