Egyptian authorities on Wednesday called for restraint in the face of outrage over a film deemed offensive to Islam that has raised fears of renewed sectarian tensions.
The government denounced the film as "offensive and immoral" but called on Egyptians to exercise restraint in their reactions amid fears among members of the Coptic Christian minority of reprisals.
"The film is offensive to the Prophet and immoral," the cabinet said in a statement read by Prime Minister Hisham Qandil.
"We call on the great people of Egypt to exercise restraint when expressing their anger," it said.
The cabinet said Tuesday's protests which saw demonstrators scale the walls of the US embassy in Cairo were "regrettable" and that it was Egypt's duty to protect all diplomatic missions.
The statement came in response to a film portraying the life of the Prophet Mohammed, which touches on themes of paedophilia and homosexuality, and which sparked a deadly attack in Libya that left Ambassador Chris Stevens and three other US officials dead.
Egyptian President Mohamed Morsi tasked the Egypt's embassy in Washington to "take all legal measure against the producers of the film that is offensive to Prophet Mohammed," the official MENA news agency said.
Authorities said that four people were arrested after breaching the wall of the US embassy, MENA reported, while officials said security had been stepped up around the mission.
There was a new protest outside the embassy on Wednesday by some 200 to 300 people, most of them hardline Islamists of the Salafist movement, amid a heavy police presence, an AFP correspondent reported.
Despite calls from some Coptic groups for Christians to join the protest, none were seen and some protesters showed their hostility with one brandishing a shoe with a cross on the sole.
The film at the centre of the protests was produced by Israeli-American Sam Bacile, according to the Wall Street Journal, but Egyptian media say that some Egyptian Copts living in the US were involved in the production.
The Muslim Brotherhood, the country's largest and most organised political force, on whose ticket Morsi stood for election, called for nationwide protests Friday in response to the film.
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The Brotherhood calls "for peaceful protests on Friday outside all the main mosques in all of Egypt's provinces to denounce offences to religion and to the Prophet," the Brotherhood's secretary general Mahmud Hussein said.
He urged all "national forces to join the protests."
The Brotherhood's political arm, the Freedom and Justice Party, strongly condemned the film which it described as "a racist crime and a failed attempt to provoke sectarian strife between the two elements of the nation -- Muslims and Christians."
The film, which depicts the Prophet Mohammed as promiscuous and talking about killing children, "goes far beyond all reasonable boundaries of the freedoms of opinion and expression," the party said.
The production, and the reactions to it, are likely to put more pressure on the Christian community, which makes up about 10 percent of Egypt's 82-million population.
Copts, who regularly complain of discrimination and have been the target of numerous sectarian attacks, have been nervous since a popular uprising ousted president Hosni Mubarak early last year and brought Islamists to power.
"Yes, we are nervous," said Hany Rasmy of the Maspero Youth Union, a prominent group of Coptic activists.
"We have been nervous in fact since the Islamists came to power," he told AFP.
"The film is offensive, there is no question about it. Any religion being attacked needs solidarity.
"We have been subjected to offence, our religion and personally, for years. We know more than anyone what it means to have your religion offended," Ramses said.
He urged authorities to reassure the country's Christians and other minorities.
"The president has to reassure all minorities and all Egyptians that they will be protected, that their property and places of worship need to be respected," he said.