Three people, including a deputy superintendent of police (DSP), were killed while 24 people were injured in a blast near a police van at Quetta's Fatima Jinnah Road, officials said on Wednesday.
Speaking to the media, DIG Operations Fida Hussain said that a police mobile from the City police station was in the area around 7pm when a loud explosion took place.
He said that the nature of the blast was being ascertained, but added that 2-2.5 kilogrammes of explosives were used.
Hussain also identified one of the deceased as a DSP, adding that 24 people — including police officials — were injured.
Quetta Civil Hospital Spokesperson Dr Waseem Baig said that the injured were being transported to the hospital for medical treatment.
Balochistan Chief Minister Mir Abdul Qudoos Bizenjo, in a statement, strongly condemned the incident. He also directed hospitals to impose an emergency and for all doctors and paramedical staff to ensure their presence.
"Cowardly terrorists targeted innocent citizens in a terrorist attack," he said. "Efforts are being made to disrupt peace in Quetta and the province under a planned and well-thought-out conspiracy."
The chief minister said terrorists and their sponsors were receiving "external support", directing the IG to submit a detailed report of the incident.
"All resources should be utilised to bring those responsible for the incident to justice," the chief minister said in his directives, also telling officials to make security arrangements in the city more effective.
Meanwhile, Karachi Administrator Murtaza Wahab prayed for those killed and injured in the incident. "Terrible news coming from Quetta," he said on Twitter.
There has been an uptick in violence in Balochistan with several attacks and explosions reported since the start of the year.
Last month, at least 13 terrorists were killed and seven security personnel, including an officer, martyred during armed attacks on two security forces' camps in the province's Naushki and Panjgur districts.