Afghan police shot dead four people protesting yesterday against cartoons of the Prophet Muhammad that have unleashed waves of rage across the Muslim world.
Tens of thousands of Muslims also demonstrated in the Middle East, Asia and Africa over the drawings, first published in Denmark, then Norway and then several other European countries.
The 12 cartoonists whose work touched off the violence were yesterday reported to be in hiding, frightened, and under police guard.
In Iran a crowd pelted the Danish embassy with petrol bombs and stones for a second day.
Protesters hurled a petrol bomb and broke windows at Norway's mission.
Iran's supreme leader, Ayatollah Ali Khamenei, called the cartoons a scandal, particularly as they came "from those who champion civilisation and free expression".
In a speech aired on state-run radio, Ayatollah Khamenei said the drawings were part of a "conspiracy by Zionists who were angry because of the victory of Hamas".
The cartoons were first published in September, four months before the Palestinian elections.
Afghan crowds attacked a base of Nato Norwegian troops with guns and grenades and police opened fire, bringing the death toll in protests against the cartoons to nine.
F-16 warplanes flew overhead in a show of force while the Norwegians fired tear gas, rubber bullets and warning shots, managing to restore order by early evening.
After rioters set Danish missions ablaze in Syria and Lebanon at the weekend, the European Union presidency issued a strongly worded warning to 19 countries across the Middle East that they were obliged to protect EU missions.
Iran's ambassador to Vienna said an attack on Austria's embassy in Tehran on Monday was directed at "the EU presidency" rather than Austria itself, current holder of the presidency.
Accusing "radicals, extremists and fanatics" of fanning the flames of Muslim wrath to "push forward their own agenda", Danish prime minister Anders Fogh Rasmussen repeated a call for dialogue with offended Muslims.
Depicting the Prophet is prohibited by Islam. Moderate Muslims, while condemning the cartoons, have expressed fears radicals are hijacking debate over the boundary between media freedom and religious respect.
Militants in Iraq have called for the seizure and killing of Danes and the boycott of Danish goods over the cartoons, one of which depicts Muhammad wearing a turban resembling a bomb with a burning fuse.
In London, protesters have brandished placards demanding the beheading of those who insulted Islam. One dressed as a suicide bomber but later apologised.
Copies of a British student paper which reproduced one of the cartoons were hastily shredded and the editor suspended from a student union. A French court, however, refused to order the confiscation of a magazine which planned to print the images.
Echoing calls for calm by leaders, UN secretary-general Kofi Annan said: "I urge all who have authority or influence in different communities. . . to engage in dialogue and build a true alliance of civilisations, founded on mutual respect." At least 10,000 people marched in the Bangladeshi capital and tens of thousands turned out in Niger's capital, Niamey.
Croatia became the latest country where a newspaper printed the drawings. The cartoons have appeared in Australia, Bulgaria, Denmark, France, Fiji, Germany, Hungary, Ireland, Italy, Japan, Jordan, Malaysia, the Netherlands, New Zealand, Norway, Poland, South Africa, Spain, Switzerland, United States, Ukraine and Yemen.