A bomb at a military school in Kashmir killed three cadets and wounded 11 today, police said.
Pakistan's portion of the divided Kashmir region had long been free of Islamist militant violence but there have been several attacks there over the past year.
The latest attack took place near the town of Rawalakot when cadets were going to school.
"It has yet to be determined whether it was a suicide bombing or a planted bomb," Javed Iqbal, chief of police in Pakistan-controlled Kashmir, said.
Late last month, five people were killed in a suicide attack outside a Shia Muslim meeting hall during Ashura, the Shi'ite calender's biggest event, in Muzaffarabad, capital of Pakistani Kashmir.
The violence in Kashmir has fuelled concern that the militants are trying to expand their campaign of violence in retaliation for a military offensive in their South Waziristan bastion on the Afghan border.
Hundreds of people have been killed in a wave of bomb attacks across Pakistan since the offensive in South Waziristan was launched in mid-October.
About 90 people were killed on Friday in one of the deadliest attacks in the country, when a militant drove an explosive-laden vehicle into a volleyball field in the northwestern town of Lakki Marwat.
Kashmir is at the core of a decades-old dispute between nuclear-armed rivals Pakistan and India and the cause of two of their three wars since their independence from British rule in 1947.
Separatist insurgents backed by Pakistan have been fighting Indian rule in India's part of the Himalayan region since 1989.
Reuters