Pressure is mounting on London police to arrest Muslim protestors who glorified the London bombings in revenge for cartoons of the prophet Muhammad.

On Monday the Prime Minister's office said it would back any police action in the wake of last week's protests at the Danish embassy over the cartoons first published in a Danish newspaper.

Cross-party MPs and a range of Muslims called for arrests of those responsible on the grounds that their threats were incitement to murder.

On Saturday one demonstrator dressed as a suicide bomber. The day before marchers brandished placards with slogans such as: "Butcher those who mock Islam," and "Britain you will pay - 7/7 is on its way."

Bomber apologises

On Monday the imitation suicide bomber, Omar Khayam, said he apologised "wholeheartedly" for offending families of the July 7 bombing victims.

He told reporters outside his Bedford home he found the cartoons "deeply offensive". But by wearing a fake explosive belt, he did "exactly the same as the Danish newspaper, if not worse".

Accompanied by he chairman of his local mosque and Bedford MP Patrick Hall, he said: "Just because we have the right of free speech and a free media, it does not mean we may say and do as we please and not take into account the effect it will have on others."

'Unacceptable'

Meanwhile Downing Street said in a statement the behaviour of some demonstrators was "completely unacceptable". Tony Blair's spokesman also condemned violence in Syria and Lebanon, where mobs torched Danish embassies over the weekend.

Number 10 understood the "offence" caused by the cartoons, one of which depicted Muhammad with a bomb-shaped turban on his head. "But nothing can justify the violence aimed at European embassies or at the country of Denmark."

About the London protests, the spokesman said: "We believe some of it was unacceptable but it's up to the police to decide whether to prosecute. The police have our full support in any actions they wish to take where there have been breaches of the law."

100 complaints

Scotland Yard received more than 100 complaints about the protest in the capital, the Press Association reported.

A Met spokesman said a "post-event investigation team" was reviewing evidence gathered by specialist officers on both protest days. This includes "police video and sound recording, CCTV and officers' written records".

"Where potential offences have been committed we will pass evidence to the Crown Prosecution Service. We will then take action following their advice."

Most of the offensive placards were written in a similar handwriting with a black felt-tip pen, repeating the same themes.

Muslims against protests

Muslim organisations ranging from the moderate Muslim Council of Britian (MCB) to the radical Hizb-ut-Tahrir were against the protests.

MCB spokesman Inayat Bunglawala said the movement condemned campaigners who engaged in "threats or comments that incite violence". Muslims would "understand the reasons" for possible arrests later on, he added.

Hizb-ut-Tahrir, which Mr Blair wants to outlaw over claims that it supports terrorism, held a less inflammatory protest against the cartoons on Saturday.

"While strongly condemning the publication of these caricatures, we also unequivocally condemn those who are urging violent protests or inciting hatred against others," Hizb-ut-Tahrir spokesman Imran Waheed told PA.

Cross-party condemnation

Labour MP Shahid Malik, who is on the Home Affairs Select Committee, wrote to Met chief Sir Ian Blair, calling for prosecutions.

Conservative politicians such as shadow home secretary David Davis and shadow attorney general Dominic Grieve echoed the calls.

"Some of these placards are incitement to violence, and indeed incitement to murder - an extremely serious offence which the police must deal with and deal with quickly," Mr Davis told the Sunday Telegraph.