At least two policemen were martyred and 12 others injured in an explosion near Quetta's Serena Hotel on Sunday evening.
Six civilians were also wounded in the blast that targeted a vehicle carrying 15 policemen near Tanzeem Chowk, Balochistan government spokesperson Liaquat Shahwani said in a statement.
He said the improvised explosive device (IED) was fitted into a motorcycle.
The injured were shifted to hospital, where an emergency was imposed, while Counter-Terrorism Department (CTD) teams were at the scene.
Shahwani condemned the attack, saying "terrorists want to disturb Balochistan's peace and spread fear."
"[We] will bring to justice the elements trying to create disturbance in peaceful Balochistan," he added.
Balochistan Chief Minister Jam Kamal Khan also condemned the attack and expressed sadness over the martyrdom of the two police personnel.
"Terrorist elements want to ruin the province's peace. [We] will never allow terrorists to succeed in their nefarious plans," he was quoted as saying in a statement.
The chief minister directed officials to submit a report into the attack and to provide the best available treatment facilities to the injured.
Separately, a vendor was injured on Quetta's Sariab Road after unidentified persons hurled a grenade at his roadside stall where he was selling Pakistan flags and other paraphernalia ahead of 14th August.
The incidents come more than three months after a powerful bomb exploded in the parking lot of the Quetta Serena Hotel, killing five people and wounding a dozen others.
Since then, there have been a number of attacks in the city in which security personnel and civilians were wounded or lost their lives.
Late last month, at least four people were injured and a Frontier Corps (FC) vehicle was damaged in a blast in Hazar Ganji, a locality on the outskirts of Quetta.
On July 1, at least six security personnel were injured, two of them seriously, in a motorcycle bomb explosion that targeted an army convoy on Quetta's Airport Road.
Balochistan Inspector General Mohammad Tahir Rai had said that an IED had been planted on the motorcycle, which was detonated by remote control.