Gunmen on Thursday shot dead eight Pakistani police and prison staff, and wounded nine others after storming a building in the eastern city of Lahore where they were sleeping, police said.
It was the second attack in three days on security personnel in the province of Punjab, raising fears of a fresh wave of violence in the political heartland of Pakistan, which has been largely peaceful over the last year.
The attackers arrived on motorbikes and targeted a building in the densely populated area of Ichra, where up to 35 police and prison staff were living, mostly officers from the troubled northwest who were in Lahore for training.
"The gunmen came early in the morning, entered the building and opened fire," Lahore police chief Aslam Tareen told AFP.
"Eight were martyred and nine others are wounded."
There was no immediate claim of responsibility. The gunmen fled and Tareen said police were investigating who was responsible.