At least 16 people have been confirmed killed in Pakistan after a fire caused a series of explosions at a munitions cache late Monday, the police said.

The explosions leveled the specialist counterterrorism station in Kabal town of Swat Valley, in the northwestern region of Khyber Pakhtunkhwa which neighbors Afghanistan.

Swat police said Tuesday that a short-circuit in a basement storing "grenades and other explosives" was the cause of the blasts.

"It was like hell let loose on me," said Abbas Khan, 21, who had parked his car near the police station.

He said a thick cloud of dust and smoke engulfed the entire area, making it difficult to breathe.

The dead included policemen, five suspected terrorists being held for interrogation, and two brothers aged four and six who lived nearby, Akhtar Hayat Gandapur, the inspector general of Khyber Pakhtunkhwa police, told AFP.

More than 50 people are being treated in various hospitals for their wounds.

Gandapur ruled out the possibility of any terrorist activity.

"We have not yet found any material or visual evidence suggesting a suicide attack but we will look into all aspects during investigations," he said.

The intense explosion rained pieces of munition on nearby houses and streets.

"Around 300 kilograms of explosives including anti-tank and anti-personnel mines, artillery shells, and mortars were stored in the basement in addition to improvised explosive devices and suicide vests which had been recovered from the custody of terrorists," Khalid Sohail, a senior officer in the local counter-terrorism department told AFP.

Funeral prayers of nine policemen were offered Tuesday morning with their coffins draped in the national flag.

Since the start of the year, two attacks on large police bases have been linked to the Pakistani Taliban, known as Tehreek-e-Taliban Pakistan (TTP).

The TTP have long targeted law enforcement officials, who they accuse of conducting extrajudicial executions.

Pakistan has witnessed a dramatic uptick in attacks since the Taliban seized control of Kabul, focused on its border regions with Afghanistan, and Islamabad says offensives are being launched from Afghan soil.

The TTP was founded in 2007 when Pakistani militants fighting alongside the Taliban in Afghanistan splintered off to focus attacks on Islamabad as payback for supporting the U.S. invasion after the 9/11 attacks.