Journalists and diplomats have begun leaving the territories as outrage escalated across Europe and the Middle East.
Angry Palestinians briefly detained a German national in the West Bank and forced the closure of European Union headquarters in Gaza.
Two masked gunmen seized the German from a hotel in the Palestinian town of Nablus “thinking he was French or Danish, and handed him over to police after realising their mistake,” a source with the Al-Aqsa Martyrs Brigades told the Agence France Presse (AFP) news service.
“The two men were acting to protest over the cartoons,” the source said, referring to 12 caricatures of the prophet Mohammed, which first appeared in the Danish daily Jyllands-Posten in September.
A Norwegian magazine re-printed some of the images last month, fuelling tensions which have now escalated to a major diplomatic standoff including a massive boycott of Danish products in Muslim countries.
A decision by the French newspaper France-Soir to publish all 12 cartoons on February 1, followed by more than half a dozen other European newspapers, has incensed many in the Muslim world where images of Mohammed are strictly forbidden.
That the images lampoon the prophet – one of which portrays Mohammed wearing a turban in the shape of a bomb – has provoked the wrath of numerous Islamic groups.
Specific threats
The two armed Palestinian groups have threatened to target Danes, Norwegians and French nationals in the Middle East.
“All nationals and those who work in the diplomatic corps of these countries can be considered targets of the Popular Resistance Committee and Al-Aqsa Martyrs Brigades,” the groups warned.
The EU headquarters in Gaza City was shutdown and staff stayed away for fear of violence, as Palestinian gunmen gathered outside scrawling “Closed Until Further Notice” on the front door of the building.
“European provocations have placed the offices of the European churches in our line of fire,” the militants said in a statement.
“We give the Danish, French and Norwegian governments 48 hours to present their apologies.”
But a top leader of Hamas has vowed to ensure Christians are protected from attacks.
Mahmoud al-Zahar spoke during a visit to the Holy Family Roman Catholic School in Gaza City, saying “you are our brothers and you will be safe in our Palestinian homeland.”
“If anybody tries to harm you, we will stop them by legal means. We will not allow anyone to harm you or your schools or churches.”
Annan urges calm
UN Secretary General Kofi Annan has waded into the row, calling for calm and understanding on both sides.
In a statement read by his spokesman Stephane Dujarric, Mr Annan said “the freedom of the press should always be exercised in a way that fully respects the religious beliefs and tenets of all religions.”
The EU’s trade commissioner was far more damning in his criticism of the cartoons and lashed the newspapers for “throwing petrol onto the flames” and being “provocative”.
“I regard them as pretty crude and pretty juvenile, and I think, in cases of such cartoons, they are almost bound to cause offence,” Peter Mandelson told BBC radio.
Some European publications, including Jyllands-Posten and France-Soir, have apologised for giving offence, even as they strongly defended their right to express opinions on any subject.
The owner of France-Soir, Raymond Lakah, went so far as to sack the publication’s managing editor Jacques Lefranc “as a powerful sign of respect for the intimate beliefs and convictions of every individual.”
But in its February 2 edition, the paper wrote that “faced with religious intolerance and censorship, it is time to come to the defence of secularism.”
Mr Lefranc has challenged his dismissal saying it was “questionable in both reasoning and method. I reserve the option to contest it.”
Cleric calls for ‘day of anger’
From Doha, leading hardline Muslim cleric Sheikh Yussef al-Qaradawi, who heads the International Association of Muslim Scholars, has called for an “international day of anger” on February 3.
“The association calls on Muslim people, scholars, clerics and mosque imams everywhere to declare Friday an international day of protest against these offences which were unfortunately reprinted by other newspapers in several European countries,” Mr Qaradawi said.
Amid fears that Muslim outrage may see a repeat of the violence that led to the killing of controversial Dutch filmmaker Theo van Gogh in 2004, a British Muslim politician has urged “all sides now to climb down and treat this as a hard lesson in building inter-cultural ties.”
“I would underline that there needs to be a greater appreciation, particularly among Muslims living outside of Europe, that governments do not have any direct control over our print media,” Sajja Karim, a Liberal Democrat member of the European Parliament for northwest England.
But he also reprimanded newspaper editors for printing the cartoons, saying they “have a real responsibility, a democratic responsibility, to make sure that they don’t do anything which undermines the freedom that they have been given.”
As the crisis begins to affect trade between Denmark and Middle Eastern and North African countries, the Danish Prime Minister is due to meet foreign diplomats on Friday.
Anders Fogh Rasmussen, though, has this week refused to apologise for the cartoons, saying the Jyllands-Posten paper had not intended to upset Muslims.
The government “cannot make apologies on behalf of a Danish paper,” Mr Rasmussen said.
“That is not how our democracy works,” he added.