Hundreds of Afghans burned cars and threw rocks at a US military base as a demonstration in the capital Kabul against an anti-Islam film which ridicules the Prophet Mohammed turned violent.
The air was thick with smoke on the Jalalabad road, a main thoroughfare into the city centre where the crowd burned shipping containers and tyres. Sirens wailed as fire engines rushed to the scene.
At least one police vehicle was burned by the mob, according to Daoud Amin, the police chief for Kabul province.
Men grabbed rocks from the roadside and lobbed them at Camp Phoenix, a US military base that lies along the road. More than 20 police officers were slightly injured - all from being hit by rocks, said General Fahim Qaim, the commander of a city quick-reaction police force.
It was the fourth day of Afghan protests against the film. Privately produced in the United States, the low-budget video portrays Mohammed as a fraud, a womaniser and a child molester. The film sparked violent protests in many Muslim countries in recent days, many of them outside US diplomatic posts around the world.
The US ambassador to Libya was killed during an attack on the consulate in Benghazi last week; protesters also stormed the US embassy in Tunis and held violent demonstrations outside posts in Egypt and Sudan. The US has responded by deploying additional military forces to increase security in certain hotspots.
In Kabul, protesters shouted "Death to America!" and "Death to those people who have made a film and insulted our prophet!"
Police officers fired shots into the air to hold back about 800 people and prevent them from pushing towards government buildings in the city centre, said Azizullah, a police officer at the site who, like many Afghans, only goes by one name.
By late Monday morning, the protest on Jalalabad road appeared to be dying down but demonstrations were picking up elsewhere in the city. In the south-eastern part of Kabul, about 50 protesters gathered in front of a mosque, shouting "Death to America," said police officer Ahmad Shafiq.
In neighbouring Pakistan, around 3,000 students and teachers rallied against the film in the town of Chaman in south-western Baluchistan province. The crowd burned an American flag and an effigy of US president Barack Obama, said officer Mohammad Shahid.