KABUL — As many as 73 people were killed Sunday in southeastern Afghanistan’s Ghazni province when two buses collided with a fuel truck, which then exploded, officials said. Scores of others were injured, many of them critically.

The crash in Ghazni was bad even by the standards of Afghanistan’s notoriously dangerous mountain highways.

About 50 people have been confirmed dead, and another 73 people who had been on the buses were wounded in the accident, the Associated Press reported.

The crash set all three vehicles ablaze, the AP said, citing Jawed Salangi, a spokesman for the governor of the eastern Ghazni province. Records show the two buses were carrying a total of 125 passengers, Salangi said.

A bus full of passengers tried to pass the slow-moving fuel tanker on a narrow highway in Mukur District around 6 a.m. Sunday and crashed head-on into another fully loaded bus, officials said.

Both buses then collided with the tanker, which exploded and engulfed all three vehicles in flames. Large plumes of acrid smoke covered the crash area.

Hamidullah Nawroz, head of Ghazni’s provincial council, said because there were many critical injuries and the victims were taken to many hospitals, the number of fatalities could change.

The BBC, Agence France Presse, and Al Jazeera said at least 73 people were killed. Many of the remains were badly burned and body parts were scattered across the accident site, making a final body count difficult, officials said.

Ismail Kawusi, a spokesman for Afghanistan’s Ministry of Health, said rescue workers had confirmed 50 bodies so far. “It takes time, and only forensic medicine will be able to identify them,’’ Kawusi said.

The accident happened on the main highway linking the capital, Kabul, to the southern city of Kandahar. Salangi said the road had been cleared and reopened early in the afternoon.

The buses were traveling one behind the other from Kabul to Kandahar when the accident happened, said Mohammadullah Ahmadi, director of the provincial traffic department. He blamed the crash on reckless driving.

Police in the Muqur district of Ghazni, where the crash occurred, are investigating the cause of the accident, but no charges have been reported.

Ahmadi said local residents helped firefighters and first responders pull survivors from the wreckage.

Shocked survivors of the attack who were able to walk staggered out of vans that took them to receive treatment at hospitals. Some appeared to be severely burned.

Road accidents are common in Afghanistan, where roads are often in poor condition and traffic laws are rarely enforced. Residents said speeding and reckless driving are common.

The Kabul-Kandahar highway passes through areas where militant attacks have occurred, and many bus drivers are known to drive at high speeds in an attempt to avoid insurgents. But there were no reports that insurgent activity contributed directly to Sunday’s crash.

Last May, at least 18 people were killed when a minivan overturned in the western province of Badghis. In April 2013, a passenger bus collided with a damaged fuel tanker that was left on a road after a Taliban attack in Kandahar province, killing at least 45 people.

The Taliban have been waging a 15-year insurgency against the Western-backed government in Afghanistan. Last month, one civilian was killed and two others were injured as a bomb blast struck a car in the Ghazni province.

Forces from the US-led coalition are stationed in Ghazni, and insurgents are active in the southern part of the country, but the province has been largely spared from the heavy fighting seen in Helmand and Kandahar provinces since the US invasion of 2001.

In November, the World Bank approved a $250 million grant to help upgrade roads in Afghanistan’s Hindu Kush mountains, a crucial trade route that is often closed in winter by snow.

On Saturday, NATO officials said two members of the US-led coalition fighting in were in an attack on a base in southern Afghanistan. The names and nationalities of the victims were not immediately available.

International forces pulled most of their combat forces from Afghanistan at the end of 2014. The remaining troops, organized as part of an international mission called Operation Resolution Support, are serving in a training and advisory role.