Ten policemen have been killed in a suicide bombing in Afghanistan, security sources say.
At least 10 people were wounded in the attack at a police training ground, in the north-eastern city of Kunduz.
It comes two days after a suicide bomber blew himself up outside a police headquarters in eastern Afghanistan, killing eight people.
There has been a sharp rise in suicide bombings by Taleban and other militants in Afghanistan since 2005.
In the latest attack, the bomber ran up to the police as they were training and blew himself up at about 0900 (0430 GMT), officials said.
"There was a suicide bombing in front of a police station...The bombing coincided with the exercise time of the policemen," interior ministry spokesman Zemarai Bashary was quoted by AFP news agency as saying
Last month, Nato and Afghan forces began what they said was their largest offensive to date against the Taleban in the south of the country.
While there has been a rash of suicide bombings in southern Afghanistan, such attacks are relatively rare in the north.
Monday's attack is the third deadly suicide bombing in Afghanistan in three days.
Analysts say the recent bombings are the Taleban's response to being squeezed by the build-up of foreign troops in the south and east.
They are very difficult to prevent, says the BBC's Mark Dummett in Kabul.