The incident highlights China's increased concern about its money invested and people working on projects in Pakistan.
The incident comes nearly two months after China warned its citizens in Pakistan to be on alert after receiving intelligence reports about possible attacks targeting Chinese.
Pakistan is becoming more dependent on China as relations with the US have hit a low.
China is ramping up investment as part of a $54 billion project known as the China-Pakistan Economic Corridor, upgrading infrastructure, power and transport links between its far-western Xinjiang region and Pakistan's Gwadar port.
Thousands of Chinese workers are employed in the development of infrastructure projects under Beijing's 'Belt and Road' initiative.
The port and road-building projects have come under frequent attacks in Balochistan.
Protecting employees of Chinese companies, as well as individual entrepreneurs who have followed the investment wave along the China-Pakistan Economic Corridor, has been a concern for Chinese officials.
Last year, two Chinese nationals, believed to be Christian missionaries, were abducted from Quetta and killed by the Islamic State group in the restive Balochistan province.
The couple had reportedly been "preaching" in Balochistan under the garb of learning Urdu.
Pakistan faces an "unprecedented situation whereby growing foreign direct investment is accompanied by a significant increase in the physical presence of foreign nationals," said a researcher of a security consultancy.