"The United States urges the Hong Kong authorities to exercise restraint and for protesters to express their views peacefully," White House spokesman Josh Earnest told reporters.
"The United States supports universal suffrage in Hong Kong in accordance with the Basic Law and we support the aspirations of the Hong Kong people.
"We have consistently made our position known to Beijing and will continue to do so," he said.
Earnest also said that the position of chief executive in Hong Kong would be given more credibility if the people of the semi-autonomous Chinese city could freely choose its candidates for the job.