An improvised explosive device fixed to a motorcycle has exploded in northern Afghanistan, killing at least six people, a local official has told Al Jazeera.

Monday's attack happened in the busy market of Dasht-e Archi district of Kunduz province, a provincial police spokesman said. 

"At least two women and four men were among the dead. At least six other people were injured in this attack," said Al Jazeera's Charles Stratford, reporting from the capital, Kabul.

In a separate attack, two US Army soldiers were killed when their vehicle was struck by a homemade bomb in the Afghan capital, defence officials said. In a statement, NATO said the troops had been killed by an "enemy attack in eastern Afghanistan".

A total of 63 NATO troops have been killed this year, 46 of them Americans.

It was not immediately clear who was behind the attack.

The blast came a day after a suicide bombing at a volleyball tournament in Paktika province killed more than 60 people.

Our correspondent reported that the Afghan security forces accused Haqqani network for the Paktika attack. The network operates predominantly from across the Pakistani border.

"The intelligence agency here said the suicide bomber was operating under control of what it describes as a shadow Haqqani network," said Stratford.

The assault on Sunday coincided with the lower of house of parliament approving agreements that will allow 12,500 NATO troops, including more than 9,000 Americans, to remain in the country next year.

The Haqqani network, which was designated a terrorist organisation by the US in 2012, has been blamed for large-scale attacks on government and NATO targets across Afghanistan as well as for many kidnappings and murders.

Source: Al Jazeera