HONG KONG (AP) — The U.S. government has stepped up its safety warning to travelers to Hong Kong because of increasingly violent protests in the Chinese city.

The State Department's Level 2 travel advisory issued Thursday urges "increased caution in Hong Kong due to civil unrest" and tells travelers to avoid demonstrations and to "exercise caution if unexpectedly in the vicinity of large gatherings or protests."

The protests were sparked by proposed extradition legislation that could have seen suspects sent to mainland China for trial. They have morphed into calls for broader democratic reforms in the former British colony and investigations into alleged police abuse of force.

The territory's crucial travel industry has suffered as tourists put off their visits. Australia, Ireland, Britain, and Japan have already issued Hong Kong travel warnings.