A man armed with a gun and grenades attacked a school in southern Pakistan during a prize distribution ceremony on Saturday, killing its principal and wounding six children before fleeing.
Police officer Nasir Mehmood said the attacker struck as dozens of children were gathered outside at their private school in Karachi to receive the results of their annual exam.
TV showed panicked relatives of the wounded children, who were between the ages of 8 and 10, crying outside the school in the port city's Ittehad Town neighborhood.
There was no immediate claim of responsibility.
Another police officer, Asif Ijaz Sheikh, said the slain principal was a local leader of the Awami National Party (ANP). He said police were still investigating the identity of the attacker, who threw two grenades and then opened fire on Khan and children who were standing near him.
Karachi has been the scene of scores of bomb and gun attacks in recent years. Gangs controlled by various groups, including the city's two main political parties the Muttahida Quami Movement and the ANP, have also been blamed for targeted killings of their rivals.
The MQM primarily represents the Urdu-speaking descendants of those who came to Karachi from India soon after the birth of Pakistan.
The group's main rival, the ANP, represents ethnic Pashtuns from Pakistan's northwest.
The ANP also has a tense relationship with the Pakistani Taliban, and the militants in recent years have targeted several party leaders, including one senior politician, Bashir Bilour, who died in a suicide attack in December 2012.
Also Saturday, a suicide bomber blew himself up near a police patrol in a bazaar in the northwestern town of Mardan, killing an officer and wounding two policemen and two passers-by, senior police officer Jafar Khan said.
He said other police spotted an associate and killed him after a short chase.
No one claimed responsibility, but the Pakistani Taliban often target police and security forces in the region and elsewhere in the country.
Associated Press writer Riaz Khan in Peshawar, Pakistan, contributed to this report.