Hong Kong (CNN Business) A Hong Kong tycoon known for his outspoken support of the city's pro-democracy movement and criticism of China was arrested Friday, along with two other prominent pro-democracy figures.

A police spokesman said that three men aged 63 to 72 have been arrested for "illegal assembly" in relation to a protest march on August 31, 2019

Mark Simon, assistant to Jimmy Lai, owner of media company Next Digital, confirmed to CNN that his boss was among those arrested early Friday morning.

Lai is also facing one additional charge of "criminal intimidation," a police spokesman said. The three will appear in court May 5,and if convicted could face up to five years imprisonment.

Tam Man-kei, director of Amnesty International Hong Kong, said in a statement that their arrest for taking part in a largely peaceful process was "unjustifiable."

Read More