The governor of the northern Afghan province of Kunduz has been killed along with at least 14 others in a bomb blast at a mosque, officials say.
Governor Muhammad Omar was attending Friday prayers in Taloqan, capital of neighbouring Takhar province.
Provincial security chief Shah Jahan Noori confirmed he had died and said at least 20 people had also been wounded.
It is not clear if explosives had been planted or whether a suicide bomber was involved, the authorities say.
There was no immediate claim of responsibility for the bombing.
"The situation is chaos, we do not know whether it was a suicide attack or whether the bomb was already planted in the mosque," Mr Noori said.
Meanwhile there were reports from eastern Afghanistan that Nato forces had killed at least five men who fired on a Nato helicopter in Khost province.
Details of the incident were not immediately clear. The International Security Assistance Force (Isaf) said the force would send investigators to Khost to investigate allegations that the helicopters had killed civilians.
Mr Omar was originally from Takhar province. He was known to have been close to President Hamid Karzai, and had survived a number of previous attempts on his life for which he blamed the Taliban.
His brother was assassinated by the Taliban last year.
The insurgency in Afghanistan is still fiercest in the south and east, but security has been deteriorating in the once peaceful north.
Mr Omar had repeatedly warned that the Taliban and al-Qaeda were gaining ground in Kunduz and had called for security reinforcements.
In an Afghan television interview last week, Mr Omar said that if security was not increased in Kunduz, insurgents would not only be a threat to northern Afghanistan, but to neighbouring countries.
The province was being used by insurgents to stage attacks throughout the region, he said.
Northern Takhar has been the scene of escalating violence amid intensified military operations by Nato and Afghan forces in recent days.
Sixteen militants were killed in air raids and ground fighting overnight Wednesday in several districts of Takhar, Mr Noori said.
More than a dozen insurgents were wounded, he added.
The BBC's Bilal Sarwary in Kabul says there has also been a wave of assassinations of government officials in recent months.
Two weeks ago the Taliban killed the deputy governor of the eastern province of Ghazni.