At least six people have been killed in a suicide bomb attack in northern Afghanistan after the bomber entered a meeting of military and political leaders in Takhar.

A provincial police chief, at least two Afghan policemen and two German soldiers died in the attack.

They were meeting in the capital of northern Takhar province to discuss an operation against insurgents, and at least another 10 people were injured, including the provincial governor, said the governor's spokesman Faiz Mohammad Tawhidi.

NATO's commander for the northern region, German Major General Markus Kneip, was among the wounded but not seriously hurt, General Rainer Glatz told reporters in Berlin.

The most high-profile casualty was General Dawood Dawood, police chief of north Afghanistan, a former deputy interior minister.

The loss of such a prominent and influential leader is a big blow to a force which is struggling to professionalise and shake off a reputation for abuse and corruption as foreign forces prepare to hand over security responsibilities in coming years.

He had been energetic opponent of the growing insurgent movement in the north, fostering state-sponsored armed self-defence groups known as the Afghan Local Police and organising campaigns against the Taliban.

The day of his death he held a news conference announcing the start of operation Hope, which aimed to oust the insurgents from Takhar and neighbouring Kunduz, where they have only gained a strong foothold in recent years.

Takhar was once so peaceful that there is no major permanent base for foreign troops there. German troops supervise the area from a base in neighbouring Kunduz province.

But violence has risen sharply in recent months, as the insurgency gathers strength in northern areas.

The Taliban claimed responsibility for the attack, saying they were targeting top regional leaders.