On Monday Kofi Annan, the UN secretary-general, expressed alarm and urged restraint, but oil giant Iran, which is reviewing trade ties with countries that published the cartoons, vowed to respond to what it called "an anti-Islamic and Islamophobic current".
In Tehran on Monday, about 200 people pelted the embassy of Austria, the current EU president, with petrol bombs and stones over the cartoons and Iran's nuclear confrontation with the West. The mission did not catch fire and police prevented people from storming it.
Further demonstrations were planned for later on Monday outside the Danish and Norwegian embassies in Tehran.
Denmark has been the focus of Muslim rage as the images, one showing the Prophet Muhammad with a turban resembling a bomb, first appeared in a Danish daily. Muslims in the Gulf Arab region have intensified a boycott of Danish goods.
The furore has developed into a clash between press freedom and religious respect, with many advocating a middle way.
For Muslims, depicting the prophet is prohibited by Islam, but moderate Muslim groups, while condemning publication of the cartoons and bridling at what they see as provocation, expressed fears about extremists hijacking the affair.
Countries where the controversial cartoons have been printed so far:
Ukraine, Bulgaria, Denmark, France, Germany, Italy, Spain, Switzerland, Hungary, New Zealand, Poland, the United States, Japan, Norway, Malaysia, Australia, Jordan and Morocco
Philippe Douste-Blazy, the French foreign minister, said, in a view echoed by other leaders after the weekend riots in Beirut and Damascus: "I call on all Arab countries to talk with moderation about what is happening. Let's keep it calm."
Ukraine became the 18th country where papers published the cartoons, joining Bulgaria, Denmark, France, Germany, Italy, Spain, Switzerland, Hungary, New Zealand, Poland, the US, Japan, Norway, Malaysia, Australia, Jordan and Morocco.
Furious Muslims once again took to the streets on Monday. One protester was killed in Afghanistan in clashes with police. Another person died at the weekend when flames forced him to jump from the burning Danish consulate in Beirut.
Call for execution
Speaking from Beirut, Omar Bakri Mohammad, leader of the Islamist group Al-Muhajiroon which is banned in Britain, called for those who blaspheme against the prophet to be executed.
"In Islam, God said, and the messenger Muhammad said, whoever insults a prophet, he must be punished and executed," he told BBC radio by telephone.
Britain issued a stern warning after a small group of protesters caused a storm by marching in London with placards threatening beheadings and bloodshed.
Chirac phoned the Danish PM
to express solidarity
"The attacks on the citizens of Denmark and the people of other European countries are completely unacceptable as is the behaviour of some of the demonstrators in London over the last few days," it said in a statement.
Moderate Muslim groups as well as Western leaders condemned the weekend violence and calls to arms and urged calm.
The prime ministers of Turkey and Spain, in an opinion piece for the International Herald Tribune newspaper, said: "With growing concern, we are witnessing the escalation in disturbing tensions.
"We shall all be the losers if we fail to immediately defuse this situation, which can only leave a trail of mistrust and misunderstanding between both sides in its wake," Tayyip Erdogan and Jose Luis Rodriguez Zapatero said in the joint article, adding: "Let the voice of reason be heard."
But Iran, which has withdrawn its ambassador from Denmark, saw things differently, saying the cartoons "launched an anti-Islamic and Islamophobic current which will be answered".
In Tehran, Golamhossein Elham, the Iranian government spokesman, said: "It was an ugly measure. The Islamic republic of Iran is prepared to sacrifice its life for its belief in Islam and the honour of the Holy Prophet."
Police fired on protesters in
Afghanistan, killing one
Manouchehr Mottaki, Iran's foreign minister, called for an emergency meeting of the Organisation of the Islamic Conference to discuss what he called Islamophobia in the West.
Meanwhile, Iran's largest selling newspaper, Hamshahri, announced it would be holding a contest on cartoons of the Holocaust in response to the publishing in European papers of caricatures of the Prophet Muhammad.
All day Monday there was a flurry of public statements as well as behind-the-scenes diplomatic activity to prevent divisions deepening between Muslim countries and the West.
Jacques Chirac, the French president, telephoned Anders Fogh Rasmussen, the Danish prime minister, on Monday to express solidarity with Denmark and to examine how to calm the situation.
European Union ambassadors meet on Monday to examine diplomatic options to try to defuse the tensions. Lebanon apologised to Denmark for the burning of its consulate. More than 300 people have so far been arrested.
Denmark advised its citizens to leave Lebanon and Syria and warned against travelling to other Middle Eastern destinations.
Chechnya's pro-Moscow government on Monday banned Danish humanitarian organisations from the shattered region.
There were new protests outside EU offices in Gaza on Monday and in several nations including Finland. In Afghanistan, one man was shot dead in clashes between protesters and police.
Other protests took place in India, Indonesia and Thailand.