Thousands of Chinese military personnel waving red flags reportedly paraded at a sports stadium in a city across the border from Hong Kong on Thursday, raising concerns of China's possible military intervention in continued unrest in Hong Kong.

AFP said that armored vehicles were also seen inside the stadium in Shenzhen City, and dozens of supply trucks and armored personnel carriers were parked outside the stadium, which is located seven kilometers from Hong Kong. 

The report said that some of the personnel inside the stadium had armed police insignias on their camouflage fatigues. 

Reuters reported earlier that the armed police conducted exercises on quelling protests at the stadium. 

Meanwhile, the Hong Kong-based Apple Daily reported that Chinese President Xi Jingping instructed a swift suppression of the protests through strict law enforcement, instead of military intervention.