Gunmen attacking a luxury hotel killed a guard at the entrance and entered the building, Pakistan’s military said.
“Up to four armed men entered the Pearl Continental hotel in Gwadar and opened fire,” Balochistan provincial home minister Ziaullah Langu told AFP by telephone.
He said the “majority” of guests had been evacuated and security forces were engaging the militants.
“However, there are reports of a few people sustaining minor injuries,” he added.
Mohammad Aslam, the on-duty officer in Gwadar, said he could hear gunfire but that the operation was coming to an end.
“There were no Chinese or Pakistani guests in the hotel”, he said, adding that only staff were present in the building.
No group immediately claimed responsibility for the attack.
The attack came three weeks after separatist gunmen targeting naval and security forces killed 14 people after forcing them off buses in Balochistan.
Pakistan’s poorest and largest province, Balochistan has been rocked by separatist, Islamist and sectarian insurgencies for years.
Pakistani security forces have been targeting insurgents in the province since 2004, and have also been repeatedly accused by international rights groups of abuses there. The military denies the allegations.
Balochistan is also host to a number of major projects under the multi-billion dollar China-Pakistan Economic Corridor (CPEC).
The massive infrastructure project seeks to connect the western Chinese province of Xinjiang with Gwadar, on the Arabian Sea.
But it has also drawn its share of attacks, particularly by separatists who have long complained that residents do not receive a fair share of profits from the province’s resources.
Violence in Pakistan has dropped significantly since the country’s deadliest-ever militant attack, an assault on a school in the northwestern city of Peshawar in 2014 that killed more than 150 people – most of them children.
But militants still retain the ability to carry out attacks, and analysts have long warned that Pakistan is yet to tackle the root causes of extremism.