|General Daud was attending a meeting with other officials when the bomber struck, reports say|
The police commander for northern Afghanistan has been killed in a suicide bomb attack on the
provincial governor's compound in Takhar.
Gen Mohammad Daud Daud is one of at least six people killed in the attack, claimed by the Taliban.
Two German soldiers were killed and Gen Markus Kneip, commander of foreign troops in north Afghanistan, wounded.
Afghanistan has seen a series of attacks in recent months by militants on police and military targets.
Takhar provincial Governor Abdul Jabar Taqwa is among those wounded, officials said.
Gen Daud was former military commander of the Northern Alliance, the Afghan forces who fought the Taliban.
The latest attack will be seen as significant because it has struck an area of the country's north which has been seen as relatively secure.
The BBC's Paul Wood in Kabul says the attack is a propaganda victory for the Taliban and a blow to wider, counter-insurgency efforts.
Gen Daud was in charge of all interior ministry forces in northern Afghanistan and is the most senior figure to be killed so far in a Taliban "spring offensive".
He was highly thought of by Nato because he got the job done, our correspondent adds.
Gen Daud was a former deputy interior minister for narcotics.
He also served as the bodyguard to Ahmad Shah Massoud, who commanded the Northern Alliance.
The attack occurred at the compound of Gov Taqwa in the provincial capital Taloqan, where officials were having a meeting.
The bomber, wearing a police uniform, was waiting in the corridor when officials came out, our correspondent says.
At least six people were killed in the explosion, including Gen Daud and the provincial police chief Shah Jahan Nuri.
At least 10 Afghans were injured, including the governor, he added.
Early reports said three German soldiers had been killed, but this was later corrected to two, with three wounded.
An spokesman for the Nato-led International Security Assistance Force (Isaf) confirmed that Gen Kneip was in the compound at the time but "was not killed".
German troops are based in neighbouring Kunduz province, and have oversight of Takhar.
The province was until recently a relatively quiet area of Afghanistan, but tensions rose in May after a Nato-led night raid in Taloqan which killed four people.
A crowd of 2,000 people took to the streets to protest against the attack, claiming the victims were civilians.
Nato said the group were insurgents.
Police opened fire on the demonstrators, killing 12 people and wounding 80.
A smaller protest the following day saw the provincial police chief's compound attacked.