The United States is urging China to exercise restraint in Hong Kong, where thousands of pro-democracy demonstrators have taken to the streets. The protesters were angered by Beijing's decision to only approve candidates that it sanctions for Hong Kong's leadership elections in 2017.
Police in Hong Kong have fired tear gas in attempts to disperse thousands of pro-democracy demonstrators who have jammed the city's financial district in defiance of government warnings for them to leave.
The Chinese government says the protests are illegal.
The protests are the worst unrest in Hong Kong since Beijing took control of the one-time British colony in 1997.
Britain called for "constructive" talks that would lead to a "meaningful advance for democracy." In Washington, the White House said the legitimacy of Hong Kong's chief executive would be enhanced after the elections if the territory's residents had a genuine choice of candidates.
But Chinese Foreign Ministry spokeswoman Hua Chunying defiantly told a news briefing in Beijing, "Hong Kong is China's Hong Kong." She said China firmly opposes "any form of support" by foreign countries for what it said were "illegal" protests.
Some have called the student-led protests the "Umbrella Revolution," as demonstrators have hoisted umbrellas against the sun and as flimsy protection against the police use of pepper spray.
WATCH: Raw video interviews with student protesters in Hong Kong:
In Washington, White House spokesman Josh Earnest said the U.S. is calling on both sides to exercise caution.
“The United States urges the Hong Kong authorities to exercise restraint and for protesters to express their views peacefully," said Earnest.
He also said the U.S. has been clear in its support of Hong Kong voters in the upcoming elections.
“We have been very consistent in voicing our support to the People's Republic of China for universal suffrage and for the aspirations of the Hong Kong people and we are going to continue to do so," he said.
At the State Department, spokeswoman Jen Psaki said the U.S. also backs the effort of Hong Kong voters to have a say in their choice of candidates in the leadership elections.
“We believe that universal suffrage and the ability of the people of Hong Kong to have a genuine choice of candidates is something that they should have. That is a concern that we have expressed directly to China," said Psaki.
The White House declined to say if President Barack Obama will raise the issue the Hong Kong protests during a November trip to Beijing but, said the president will state the importance of the protection of basic universal human rights.
