Protests have intensified in Gwadar district against China's multi-billion belt and road project, with people fearing threats to their livelihoods.
Media reports from Pakistan said Chinese investors were concerned over the slow pace of construction on the projects.
The ambitious CPEC was launched in 2015 when Chinese President Xi Jinping visited Pakistan.
A notification issued by the Prime Minister's Office said Khalid Mansoor has been appointed as Special Assistant to the Prime Minister on CPEC Affairs with immediate effect.
China on Thursday took note of the arrest and said it will work with Islamabad to "go to the bottom of the truth" to punish the perpetrators.
CPEC is economic initiative, has not affected stand on Kashmir issue: China defends contentious project
India has protested to China over the CPEC, the flagship project of China's Belt and Road Initiative (BRI), as it traverses through Pakistan-occupied Kashmir.
All party leaders in the House agreed that the debate should be rescheduled as the Supreme Court's determination on the constitutionality of the bill had not yet reached Parliament, officials said.
Nazar, who calls himself a freedom fighter of Baloch Liberation Front (BLF) demanded an independent Balochistan.
The CPEC links China's Kashgar in Xinjiang province with Pakistan's Gwadar port in Balochistan through a network of roads, railways and highways.
India has objected to the USD 50 billion CPEC as it passes through Pakistan-occupied Kashmir.
Doklam standoff: Important to not change status quo at sensitive points at India-China border, says Indian envoy
The 73-day standoff at Doklam in Sikkim where Chinese military attempted to build a road close to Chicken Neck corridor has sparked a new round of tensions at the border.
US President Trump's pressure on Pakistan may boost Chinese ties, let China build military base near Chabahar port: report
The proposed base at Jiwani is located just a stone's throw from Chabahar port being jointly developed by Iran, India and Afghanistan to ensure a trade corridor for Indian exports to Afghanistan.
The security cooperation agreement was reached when Meng Jianzhu met visiting Pakistani Foreign Minister Khawaja Asif the day before in Beijing.
Chinese Foreign Minister Wang Yi asserted that the purpose of the USD 46 billion China-Pakistan Economic Corridor was economic.