Spate of attacks: Afghan soldiers watch as the wreckage of an army bus is taken away from the scene of the attack. Photo: AFP

Kabul: Two American soldiers were killed in Afghanistan by a Taliban bomb on a NATO convoy near the US Bagram Airbase north of Kabul, a US defence official says.

The blast left a three metre-long blackened fissure in the road on Friday night, a witness said, as helicopters buzzed overhead on Saturday morning.

"Two International Security Assistance Force service members died as a result of an enemy forces attack in eastern Afghanistan on December 12, 2014," a coalition press release said on Saturday.

Afghan security guards inspect the damaged bus at the site of a suicide attack. Photo: AP

The coalition, as per its policy, declined to give the soldiers' nationality but a US defence official in Washington confirmed the two were American.

Advertisement

The bomb was the latest in a spate of deadly attacks in and around the Afghan capital as international forces leave the country.

It came two days after the US closed a prison that held foreign detainees on the airfield, which is in Parwan province, the only province adjacent to the capital that is usually relatively peaceful.

It also followed a NATO air strike on Thursday that killed five people in the same province. Afghan officials said the casualties were civilians. The coalition said it was investigating the allegations, but that they were identified from the air as militants before the "precision" strike.

Spate of attacks

The Taliban also killed a Supreme Court official and a dozen mine clearers, but suffered heavy losses from intensifying violence ahead of the withdrawal of most international troops in the next two weeks.

In Kabul on Saturday, a bomb ripped through a bus carrying soldiers, killing at least six of them, mangling the vehicle and sending a column of black smoke over the capital.

"A suicide bomber on foot detonated his explosives at the door of a bus carrying army soldiers," said Hashmat Stanekzai, a spokesman for the Kabul police chief.

Earlier, gunmen shot dead senior Supreme Court official Atiqullah Raoufi as he left his home in the city.

The Taliban, ousted from power by US-backed Afghan forces in 2001, claimed responsibility, but did not say why it had killed him. The hardline Islamist insurgents run their own courts in parts of the country and consider the official judiciary to be corrupt.

Heavily fortified Kabul has seen multiple attacks in recent weeks, including several on army buses and a suicide bomb that killed a German citizen in a French cultural centre during a performance of a play that denounced suicide attacks.

Fatalities and injuries among Afghan security forces and civilians peaked this year to the highest point since the US-led war began in 2001, as foreign forces rapidly withdrew most of their troops from the interior of the mountainous nation.

About 5000 Afghan police and soldiers have been killed, and more than 1500 civilians were killed in the first half of the year. About 13,000 foreign soldiers will remain in Afghanistan next year, down from a peak of more than 130,000.

Fighting has extended long beyond the traditional summer season, with the Afghan government also inflicting heavy casualties on the Taliban. The army and police say they killed more than 50 militants nationwide in the past 48 hours.

The Taliban have been fighting a guerrilla war ever since their five-year regime was toppled. They now have a strong presence in most of the provinces surrounding Kabul.

Reuters