Afghanistan Koran protests: UN compound in Kunduz set alight
Part of a UN compound in the Afghan city of Kunduz has been set alight amid fresh protests against the burning of the Koran by US soldiers.
Four people were killed and dozens injured in clashes in the city, according to local doctors. Three more people were killed in the southern province of Logar.
More than 20 have died since the protests began on Tuesday.
On Friday Nato's Afghanistan commander Gen John Allen had appealed for calm.
US personnel apparently inadvertently put the books into a rubbish incinerator at Bagram air base, near Kabul.
A group of 500 demonstrators attacked police defending the UN compound with stones, metal sticks and sharp objects, the deputy chief of police in northeastern Kunduz province said.
"Then warning shots were fired. But they refused our warnings," he added.
Eyewitnesses reported gunfire in the city and several buildings being set alight.
"The demonstrators have burned several shops and part of a government building", a shopkeeper in Kunduz told the BBC.
"[There is] a lot of gunfire going on. There is chaos. I have seen a lot of people with bloody clothes and bodies", he said.
The governor's house in Laghman province also came under attack on Saturday.
Eyewitnesses reported seeing smoke coming out of one of the building's security towers set alight by demonstrators.
Elite Afghan forces then arrived to secure the compound.
Doctors at Laghman hospital told the BBC that 21 people had been injured, two of them critically.
Police had detained 17 armed men from among the demonstrators in Laghman, the provincial governor Mohammad Iqbal Azizi told reporters.
Demonstrations were also reported by police and government officials in Paktia, Nangarhar and Sari Pul provinces.
Friday was the deadliest day of unrest so far. At least 12 people were killed across the country as mobs charged at US bases and diplomatic missions.
Eight of the deaths reported on Friday were in western Herat province, which had seen little unrest previously.
Earlier on Friday, Gen Allen called on "everyone throughout the country - Isaf [International Security Assistance Force] members and Afghans - to exercise patience and restraint as we continue to gather the facts".
"Working together with the Afghan leadership is the only way for us to correct this major error and ensure that it never happens again," he said in a statement.
US President Barack Obama has also apologised for the Koran-burning incident.
In a letter to his Afghan counterpart Hamid Karzai, Mr Obama said the books had been "unintentionally mishandled".
Muslims consider the Koran the literal word of God and treat each book with deep reverence.
On Thursday the Taliban had called on Afghans to attack "invading forces" in revenge for "insulting" the Koran.
Last year, at least 24 people died in protests across Afghanistan after a hardline US pastor burned a Koran in Florida.