A suicide bomber blew himself up outside a stadium Tuesday night as supporters of a nationalist party were leaving a rally in insurgency-hit southwest Pakistan, killing at least 13 people and wounding around 30 others, police and hospital officials said Wednesday.

Local police chief Majeed Qaisrani said the blast occurred near a graveyard close to the stadium on the outskirts of Quetta, the capital of Balochistan province. The body parts of the attacker were recovered, he said.

In initial figures after the incident Balochistan health minister, Bakht Muhammad, said 12 people were killed and 31 had been injured, seven of which were in a critical condition.

Waseem Baig, a spokesman for a government hospital, said it had received 13 bodies and dozens of wounded, some in critical condition.

Medical staff and relatives of the victims were seen rushing to the hospital, carrying the wounded in blood-soaked clothes.

There was no immediate claim of responsibility for the attack.

The rally was held to mark the anniversary of the death of Sardar Ataullah Mengal, a veteran nationalist leader and former provincial chief minister.

The leader of the Balochistan National Party, Akhtar Mengal, was unharmed in the attack but some of his supporters were among the dead and wounded, senior police officer Usama Ameen said.

Mengal is a vocal critic of the government and often holds rallies to demand the release of missing Baloch nationalists.

Balochistan Chief Minister Sarfraz Bugti condemned the bombing as a “cowardly act of the enemies of humanity,” ordering the best possible medical care for the wounded and a high-level probe to bring the perpetrators to justice.

Balochistan has long been the scene of a low-level insurgency, with groups such as the Balochistan Liberation Army demanding independence from the central government. The separatists have largely targeted security forces and workers from Pakistan's Punjab province.

Although authorities say the insurgency has been subdued, violence in the region continues.

In July, gunmen abducted and killed nine people after stopping two passenger buses on a highway in Balochistan as the buses traveled from Quetta to Punjab province. Most such previous attacks have been claimed by the outlawed BLA group.

AP video shot by: Khalil Ahmed