A powerful blast targeting a military vehicle on Saturday night killed at least 15 people and wounded 32 others in southwestern Pakistan, officials said, in an attack claimed by the Islamic State group.

The blast occurred at a bus stop in Quetta, the capital of Balochistan province, and the area caught fire soon after the explosion.

A statement by the Pakistani military said the explosion targeted an on-duty vehicle and set several other vehicles on fire.

"Incendiary explosive was used. As a result nearby vehicles caught fire. Fifteen people including seven civilians were martyred," the statement said.

Provincial home minister Sarfraz Bugti and government spokesman Anwar ul Haq Kakar confirmed the death toll and put the number of wounded at 32.

The Islamic State Khorasan Province -- the Middle Eastern group's affiliate in Afghanistan and Pakistan -- released a statement claiming the attack, according to the US-based monitoring group SITE.

A suicide motorbike bomber was behind the blast, the statement said.

The local affiliate has been known to work with Pakistani militant groups in previous attacks.

Minister Bugti said firefighters were still working to put out the blaze. The nature of the blast could not immediately be determined but an investigation was underway, he said.

President Mamnoon Hussain, Chief of the Army Staff Qamar Javed Bajwa and deposed Prime Minister Nawaz Sharif all condemned the attack.

The blast came two days before Pakistan's 70th Independence Day, and the military chief said it was an effort to mar celebrations.

"Our resolve won't succumb to any challenge," he said in a statement.

Militants in past have carried out big attacks on Independence Day and other events of national importance.

Islamic State militants and the Taliban have attacked Quetta city in the past.

Balochistan, which borders Iran and Afghanistan, has oil and gas resources but is afflicted by Islamist militancy, sectarian violence between Sunni and Shiite Muslims and a separatist insurgency.

Almaghribtoday-