Afghanistan's leading Muslim clerics and U.S. President George W. Bush called separately on Wednesday for an end to violent demonstrations against cartoons depicting the Prophet Muhammad.
Four protesters were killed in the southern Afghan city of Qalat in the latest violence, on Wednesday.
"We reject violence as a way to express discontent with what may be printed in a free press," Bush said following a meeting with King Abdullah II of Jordan.
"I call upon the governments around the world to stop the violence, to be respectful, to protect property, protect the lives of innocent diplomats who are serving their countries overseas."
And while Americans believe in a free press, Bush said, "With freedom comes the responsibility to be thoughtful about others."
Earlier, members of Afghanistan's Ulama Council went on radio and television to appeal for calm.
"Islam says it's all right to demonstrate, but not to resort to violence. This must stop," Mohammed Usman told the Associated Press.
"We condemn the cartoons but this does not justify violence. These rioters are defaming the name of Islam."
Four dead as police fire into crowd
Meanwhile, police fired into the air to try to disperse hundreds of protesters, many throwing rocks, who were rioting outside Qalat's U.S. military base. Police then fired into the crowd, said provincial police chief Ghulam Nabi Malakhail.
Four were killed and 20 wounded in the volley.
Tanker trucks waiting to deliver fuel to the base were set on fire, and U.S. troops reportedly fired into the air.
Eleven people have been killed as angry demonstrations swept Afghanistan, growing in intensity in the past few days over the publication in European newspapers of the cartoons, one depicting the prophet wearing a bomb-shaped turban.
Muslim tradition forbids any depiction of Muhammad out of concern it could lead to idolatry.
The caricatures were first printed in September in a Danish newspaper, and have been reprinted in several European countries.
Protests have erupted in several Muslim countries.
Also Wednesday, about 300 Palestinians demonstrated their anger by attacking an international observer mission in the West Bank city of Hebron.
The protesters chased away the Palestinian police stationed outside the mission and tried to set fire to one of the buildings.
A spokesperson for the Temporary International Presence in Hebron said 60 members of the mission were inside at the time.
More than 1,000 people also rallied in Dhaka, Bangladesh, burning Danish and Italian flags.
Radical groups exploiting anger?
In Indonesia, the foreign minister said radical groups were exploiting the anger over the cartoons.
"The cartoons have hurt the Islamic community, so it has added to ammunition for (global) radical groups to exploit the situation and the whole thing has got out of proportion," Indonesian Foreign Minister Hassan Wirajuda told reporters.
Egypt and Saudi Arabia, two of the most religiously influential countries in the Arab world, have experienced little of the violent public outrage.
Syria and Iran, some analysts have suggested, have used the issue to stir anti-Western sentiment for political means. Some have also suggested the Taliban and al-Qaeda are using the furor to create more resistance to U.S-backed governments there.