WASHINGTON, June 13 (Reuters) - U.S. lawmakers on Thursday responded to the crisis in Hong Kong resulting from a proposed extradition law with China by introducing legislation that would require the U.S. government to justify the continuation of special treatment afforded to the territory.

The bipartisan Senate legislation, sponsored by several senior senators, would require the U.S. secretary of state to issue an annual certification of Hong Kong’s autonomy to justify special treatment under the U.S. Hong Kong Policy Act of 1992.

The proposed law, introduced by Republican Senator Marco Rubio and Democratic Senator Ben Cardin, would also require the U.S. president to identify persons responsible for the abduction of several booksellers and other individuals from Hong Kong and subject them to U.S. sanctions.

It would also require the president to issue a strategy to protect U.S. citizens and business from the effects of a revised extradition law and the U.S. Commerce Department to issue an annual report assessing whether Hong Kong was adequately enforcing U.S. and U.N. sanctions, particularly related to Iran and North Korea.

In addition, the legislation would also make clear that Hong Kong citizens should not be denied visas to the United States if they were arrested or detained in connection with protest activity there.

The legislation was expected to be introduced to the House on Thursday.

Scuffles broke out between demonstrators and police in Hong Kong on Thursday as hundreds of people persevered with a protest against the extradition law a day after police fired tear gas and rubber bullets to break up big crowds.

Protests around the city's legislature on Wednesday forced the postponement of debate on the extradition bill, which many people in Hong Kong fear will undermine freedoms and confidence in the commercial hub. (Reporting by David Brunnstrom; Editing by Steve Orlofsky)