At least two children were killed in a "suicide attack" targeting a vehicle carrying Chinese nationals in Balochistan's Gwadar district on Friday, the provincial government's spokesperson said.
Three people, including the car's driver, were also injured when a suicide bomber blew himself near the vehicle.
"Strongly condemn suicide attack on Chinese nationals' vehicle in Gwadar," Balochistan government spokesperson Liaquat Shahwani tweeted.
He said two children playing nearby had died in the explosion, while one Chinese national sustained minor injuries.
The Gwadar police control room earlier said three children had been injured in the incident. The injured were shifted to GDA Hospital in Gwadar.
The blast took place shortly after 7pm in Baloch Ward near Gwadar's Eastbay Expressway.
Shahwani said police and Counter-Terrorism Department (CTD) teams were at the crime scene, and an investigation into the incident had been launched. He lamented that "innocent children" had died in the attack.
In a tweet, Information Minister Fawad Chaudhry said the "attack in [Gwadar] is just another expression of [the] game of sabotage against the economic vision of great leadership of China and Pakistan; our enemy cannot undermine our resolve."
He added that the government "will spare no effort to bring the culprits to justice".
There was no immediate claim of responsibility for the attack.
The incident comes less than two weeks after a motorcycle bomb blast took place at Quetta's Hali Road roundabout, near Balochistan Assembly and the High Court, leaving two policemen martyred and 21 others, including 12 policemen, injured.
China is heavily involved in the development of the Gwadar port on the Arabian Sea as part of the $60 billion China-Pakistan Economic Corridor, which is itself part of China's Belt and Road infrastructure project.
There have been other attacks targeting Chinese nationals in the country in recent weeks.
Late last month, a Chinese engineer who had recently arrived in Karachi was shot at and wounded in a moving car by gunmen riding a motorcycle in the city's SITE area where he was supposed to repair imported machinery. The banned Balochistan Liberation Front had claimed responsibility for that attack.
On July 14, a bus carrying Chinese workers in the Dasu area of Khyber Pakhtunkhwa's Upper Kohistan district fell into a ravine after an explosion, killing 13 people, including nine Chinese nationals. The blast left 28 other people injured.
After initially suggesting that the incident was an accident, the government earlier this month said a suicide bomber had attacked the bus which was carrying Chinese workers to the under-construction Dasu dam.
Foreign Minister Shah Mahmood Qureshi said last week that India’s Research and Analysis Wing (RAW) and Afghanistan’s National Directorate of Security (NDS) intelligence agencies were behind the attack.