Leaders of Chinese-ruled Hong Kong widened their legal fight against the city's fledgling independence movement on Friday, targeting four more lawmakers over oaths taken at a Legislative Council swearing-in ceremony in October.

Chief Executive Leung Chun-ying and Justice Secretary Rimsky Yuen began the action on Friday after lawmakers Baggio Leung and Yau Wai-ching lost a legal appeal over their disqualification, the government said in a statement.

The government proceedings seek "to declare their oaths purportedly taken as invalid and their office as now vacant," the government said in the statement.