Hong Kong authorities are stepping up their campaign against opposition lawmakers who used their swearing-in ceremony to stage apparent protests against Beijing.

Hong Kong's government said Friday that it has started legal proceedings against four recently elected members of the Legislative Council.

The move follows the government's legal victory last month against two young separatist lawmakers who used an anti-China slur when they were being sworn in. A judge ruled that the two should be disqualified.

In a statement, the government said it has taken legal action to request that a court rule that the four lawmakers' oaths are invalid and their seats be declared vacant.

The lawmakers altered their oaths in various ways. One read her pledge in slow motion. But they were later allowed to retake them.