"Sixteen civilians died during the initial attack... Twenty-four civilians were wounded during the attack," a spokesman of the US-led forces told Agence France Presse (AFP).
The American forces said the incident erupted after their five-vehicle convoy came under attack from several directions on a busy highway between the eastern city of Jalalabad and the Pakistan border.
They said the car bomb as part of "a complex ambush" involving small-arms fire from several directions, adding that troops opened fire in self-defense.
"There were no casualties to the foreign forces, but the American forces became emotional and opened fire on Afghans in the area because they feared another bomb attack," Afghan Interior Ministry spokesman Zmarai Bashiri told CNN.
Provincial police spokesman Abdul Ghafour said the US troops were responsible for the civilian casualties.
An AFP reporter saw around seven bullet-riddled vehicles, some smeared with blood, at the site of the attack.
In a statement on its website, the Taliban claimed responsibility for the convoy attack, accusing the US forces of opening fire on civilians.
There are about 45,000 foreign troops, including 27,000 US ones, in Afghanistan.
Angry Afghans shouted anti-US and anit-Karzai slogans. (Reuters)
More than a half dozen Afghans recuperating from bullet wounds told The Associated Press that the US forces fired indiscriminately along at least a six-mile stretch.
"They were firing everywhere, and they even opened fire on 14 to 15 vehicles passing on the highway," said Tur Gul, 38, who was shot twice in his right hand.
"They opened fire on everybody, the ones inside the vehicles and the ones on foot."
Thousands of local people took to the streets, accusing the Americans of deliberately firing on the civilians, according to AFP.
The angry demonstrators blocked the road in the Marko area for several hours, shouting "Death to America, Death to Karzai", referring to the US-backed president.
NATO and US forces are often accused of firing at Afghan civilians they fear may be about to launch an attack.
Though officials say the shootings are done in self defense, they often injure or kill innocent civilians.
On December 3, two Afghan civilians were killed and five others wounded when British troops went into rampage, firing indiscriminately at civilians in Kandahar after they came under attack.
Up to 76 people, many believed to be civilians, were killed in American strikes on a village in southern Afghanistan on Monday, May 22.
Analysts believe bombings and "accidental" shootings feed resentment of the government and its Western allies and even bolsters support for Taliban.Güncelleme Tarihi: 20 Eylül 2018, 18:16