Gunmen killed at least 14 people after forcing them to disembark from buses in Pakistan's restive Balochistan province, officials said Thursday.
The attackers, who numbered around two dozen, were wearing uniforms from the paramilitary Frontier Corps, provincial home secretary Haider Ali told AFP.
They "stopped buses on the Makran Coastal Highway and gunned down 14 people", he said, adding that the four vehicles were travelling to the port megacity of Karachi from the coastal town of Ormara.
A naval official and a coast guard member were among those killed, Ali said. All the victims are believed to be Pakistani.
Provincial home minister Mir Zia Langov told AFP a full-scale investigation had been launched into the attack and to track down the gunmen, who he said had fled the scene.
"Such incidents are intolerable and we will not spare the terrorists who carried out this dastardly attack," he said.
Prime Minster Imran Khan also condemned the killings in a statement from his office.
No group immediately claimed responsibility for the attack, which came less than a week after a suicide blast in provincial capital Quetta killed 20 people.
Balochistan, which borders Afghanistan and Iran, is Pakistan's largest and poorest province, as well as the site of Islamist, sectarian and separatist insurgencies.
The Islamic State group is also active in the province, and claimed last week's attack targeting ethnic Shia Hazaras in a fruit market in Quetta.
The Pakistani military has been targeting insurgencies in the province since 2004, and has been repeatedly accused by international rights groups of abuses there. It denies the allegations.
Balochistan is also the site of the flagship project of the multi-billion dollar China-Pakistan Economic Corridor (CPEC).
The massive infrastructure project seeks to connect the western Chinese province of Xinjiang with the Arabian Sea port of Gwadar in Balochistan.
But it has also drawn its share of attacks, particularly by Baloch separatists who have long complained that residents of the province do not receive a fair share of profits from the project.
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.