At least four civilians have been killed in a Nato attack on a bus in southern Afghanistan, sparking angry anti-American protests on the streets of Kandahar city.
Nato troops opened fire on the bus in the Zhari district of Kandahar province before dawn on Monday, killing four people and injuring 18, Afghan officials said.
Nato's International Security Assistance Force (Isaf) confirmed that a woman was among those killed and said it was investigating the incident.
It said the bus had approached a slow-moving military convoy from behind at a high speed and ignored flares and other signals to slow down.
"Perceiving a threat when the vehicle approached once more at an increased rate of speed, the patrol attempted to warn off the vehicle with hand signals prior to firing upon it," Nato said in a statement.
"Once engaged, the vehicle then stopped."
The driver of the bus, who escaped unhurt, said he was about 70 to 100 meters away from a military convoy when the shooting began.
"They opened fire at us and I fell unconscious. The people who were killed were sitting in the seats just behind me," he told the AFP news agency.
'Death to America'
Nato and Afghan authorities declined to identify the international forces involved by nationality, although several Afghans said they were American.
Many Afghans took to the streets of Kandahar city after the shooting, blocking the main highway out of the city with burning tires.
They chanted "Death to America" and called for the downfall of Hamid Karzai, the Afghan president.
"The Americans are constantly killing our civilians and the government is not demanding an explanation," Mohammad Razaq, a local resident, said.
"We demand justice from the Karzai government and the punishment of those soldiers responsible."
Karzai condemned the attack and asked Nato forces to take "serious precautions" to avoid further civilian casualties, expressing "deep grief" over the incident.
Kandahar is the target of a mass offensive planned by Nato-led forces in coming months.
Haroun Mir, a founder of the Centre for Research and Policy Studies, a think-tank based in Kabul, said the Nato shooting will spark more resentment from the Afghan people at a time when international forces need their support.
"[With] the upcoming military operation in Kandahar, the US military is making an enormous effort to win people's hearts and minds and this incident will contradict all their efforts," he told Al Jazeera.
"This will be a difficult task for the US military to show to the Afghan people that they are trying to protect civilians."
PHOTO CAPTION
NATO and US soldiers stand guard in Kabul in January 2010.
Al-Jazeera