Hong Kong, April 20 -- Hong Kong's oldest and most prominent pro-democracy party is preparing to shut down amid an intensifying crackdown by China.

The Democratic Party, which has been a key part of the city's opposition movement for over 30 years, has begun the process of disbanding after receiving strong warnings from Chinese authorities, according to two longtime members who spoke with CNN.

Yeung Sum, a former chairman of the party, said the message from Beijing was clear: disband or face consequences.

"The message was that the party has to be disbanded or there will be consequences," Yeung said.

Former legislator Fred Li added that a Chinese official told him the party should not continue operating beyond the end of the year, ahea...