Three more people have died in anti-US protests in Afghanistan, bringing the total to seven over the last two days.
Some students have called the US 'invaders'
The protesters are angry over reports that interrogators at the Guantanamo Bay prison desecrated the Koran.
Two people died in a shooting near the city of Jalalabad. Another person was killed west of the capital, Kabul.
As the violence spread from Jalalabad to other parts of the country, the UN has announced that it is pulling out its international staff from the city.
Correspondents say the protests are the largest against the US since the fall of the Taleban in 2001 and have now taken place in 10 of the country's 34 provinces as well as Kabul.
At least three demonstrations took place in Kabul on Thursday.
But the BBC's Andrew North says the worst trouble was in a district north west of Jalalabad, with two people being killed when shooting broke out. It is not clear who fired the shots.
Many more are reported injured.
Jalalabad was the scene of anti-US riots on Wednesday in which four people were killed.
Another person died on Thursday after a police ammunition store was set on fire west of Kabul, and south of the capital protestors ransacked two Western aid agency compounds.
The biggest of the Kabul protests was at the university where between 200 and 300 students shouted slogans against the US.
They chanted "Death to America!" and carried banners stating "Those who insult the Koran should be brought to justice."
One group of students climbed a building and set light to the US flag, to loud cheering from the crowd.
But heavily armed police, many in riot gear, prevented anyone marching beyond the university area.
"America is our enemy and we don't want them in Afghanistan," political sciences undergraduate Ahmad Shah told the AP news agency. "When they insult our holy book they have insulted us."
Another student told the AFP news agency that the US were "invaders" of Afghanistan who had done "nothing good for Islam".
Our correspondent says that the authorities are concerned that the demonstrations are being orchestrated, and that it may be significant that so far they have all happened in the east or south.
This is where US forces are concentrated in their battle against the Taleban and other militants.
Although allegations of the Koran being desecrated appear to have been the trigger, some analysts say the protests are also a reflection of growing resentment towards the Americans in these areas of Afghanistan.
The protesters were not allowed beyond the university compound
In Jalalabad on Wednesday hundreds rioted over the allegations - reported in the American magazine Newsweek - that prison staff at Guantanamo Bay prison flushed at least one copy of the Koran down a toilet.
They caused widespread damage to property and four people were killed after two days of protests. All but essential UN staff are being withdrawn.
US authorities say they are investigating the Koran allegations.
President Hamid Karzai said the violence showed the inability of Afghan authorities to handle such protests.
Around 100 students from religious seminaries staged a demonstration over the same issue in Pakistan's northern city of Peshawar on Thursday.
Islamist parties in Pakistan have called for a nationwide strike over the issue on Friday.
Insulting the Koran or the Prophet Muhammad is regarded as blasphemy and punishable by death in both Pakistan and Afghanistan.