BEIJING (Reuters) - China will not "stand idly by" and has the potential to restore calm "quickly" if the crisis in Hong Kong "gets out of control," China's ambassador to London Liu Xiaoming said on Thursday.

"If the situation deteriorates and turns into unrest that the SAR government cannot control, the central government will not stand idly by," he said. "We have enough solutions and enough capacity to quickly suppress unrest."

Meanwhile, Benny Tai, one of the leaders of the so-called “umbrella movement” in Hong Kong in 2014, was released on bail yesterday, coinciding with a stronger wave of protests.

Tai, a law professor at the University of Hong Kong, served three months of 16 months in prison for his role in pro-democracy protests, which led to paralysis in parts of the city for 79 days in 2014. The judge, who ruled Thai released on bail his decision to say that it is unlikely to appeal one month before the sentence ends in March, according to the South China Morning Post.

Tai's release comes as Hong Kong is experiencing its biggest wave of protests in decades, which erupted in June over a controversial extradition bill that has since been suspended.

The massive protests shut down Hong Kong International Airport earlier this week, raising fears that Beijing would send troops stationed in neighboring Shenzhen to ease unrest.

The umbrella movement, founded in 2014, stems from Hong Kong residents' indignation over Beijing's proposal to elect the city's chief executive from a pre-approved pool of candidates.