Pakistan's security forces used drones and helicopters to wrest control of a southwestern town from separatist insurgents after a three-day battle, police said on Wednesday, as the number of civilians and security personnel killed in the violence rose to 58.

Saturday's wave of coordinated attacks by the separatist Baloch Liberation Army brought Pakistan's largest province to a near standstill as insurgents set off explosives and exchanged fire with security forces in more than a dozen places.

Security officials said they have killed 197 militants.

"I thought the roof and walls of my house were going to blow up," said Robina Ali, a housewife living near the main administrative building in the fortified provincial capital of Quetta.

Insurgents stormed schools, banks and police station

Fighters of the BLA, the region's strongest insurgent group, stormed schools, banks, markets and security installations across Balochistan in one of their largest operations ever, killing more than 22 security personnel and 36 civilians.

Police officials gave details of the situation on condition of anonymity as they were not authorised to speak to the media.

In the desert town of Nushki, home to about 50,000, the insurgents seized control of the police station and other security installations, triggering a three-day standoff.

"On January 31, at around 5:30 in the morning, some miscreants snuck into our homes and took over the property," said Assistant Commissioner Naushki Maria Shamoon.

"They occupied the Deputy Commissioner Complex, took Deputy Commissioner Mohammad Hussain, and his family hostage. They wanted to stop us from serving the people."

Police said seven officers were killed in the fighting before they regained control of the town late on Monday, while operations against the BLA continued elsewhere in the province.

"Helicopters and drones were used against the militants," said one security official.

Pakistan's interior ministry did not immediately respond to a Reuters request for comment.

Late night attacks

Pakistan's largest and poorest province, mineral-rich Balochistan borders Iran and Afghanistan and is home to Beijing's investment in the Gwadar deepwater port and other projects.

It has grappled with a decades-long insurgency led by ethnic Baloch separatists seeking greater autonomy and a larger share of its natural resources.

The BLA, which has urged people of the province to support the movement, said on Tuesday it had killed 280 soldiers during its Operation "Herof", or Black Storm, but gave no evidence.

Security officials said the weekend attacks began at 4 a.m. on Saturday with suicide blasts in Nushki and the fishing port of Pasni and gun and grenade attacks in 11 more places, including Quetta.

The insurgents seized at least six district administration offices during the siege, took provincial government officials hostage, and had advanced at one point to within 1 km (0.6 mile) of the provincial chief minister's office in Quetta, the police officials said.

Ahead of the attack, the BLA made announcements in mosques asking people to support and join them, saying they were waging a war to take over all state offices in the province, the officials said.

Evolving insurgency

Pakistan has blamed India for the attacks, without furnishing evidence for charges that could escalate hostilities between the nuclear-powered neighbours who fought their worst armed conflict in decades in May.

India's foreign ministry has rejected the charges, saying Islamabad should instead tackle the "long-standing demands of its people in the region".

Retired Lieutenant General Amir Riaz, who led the military in Balochistan from 2015 to 2017, said the insurgency had evolved over the last decade, adding it would likely continue to alternate between stalemate and periods of heightened violence.

"It has escalated. The response will be decisive, leading to serious capacity degradation of BLA," he said, denying that the Pakistani military has used excessive force in Balochistan.

"Ultimately, the issues are only resolved through political process and governance."