The U.S. ambassador to China, who is considering a run for the White House, on Monday condemned the harassment and beating of some foreign reporters who went to cover a planned protest gathering against the government.

It is the third time in as many weeks that ambassador Jon Huntsman has set himself publicly against the ruling Chinese Communist Party's efforts to stamp out dissent.

Lines of police checked passers-by and warned away foreign photo journalists in downtown Beijing and Shanghai on Sunday after a U.S.-based Chinese website spread calls for Chinese people to emulate the Jasmine Revolution sweeping the Middle East and assemble in support of democratic change.

Organizers have called for another round of protests this Sunday, according to a newly established Facebook page called Chinese Jasmine Revolution. Facebook is blocked in China and not widely used by Chinese.

With the global call for freedom, we sincerely put our hopes on the safety and stability of Facebook, Google and Twitter, which will facilitate China's Jasmine blooming throughout our country and bring forward the fruit of democracy, the page's founders said on their Facebook page in English and Chinese.

Before the designated protest time last Sunday, Chinese police warned foreign journalists to stay away, and many Chinese dissidents and rights activists have been detained or put under informal house arrest, apparently out of official jitters about the protest call.

An American news videographer was kicked and beaten repeatedly in the face with brooms and taken into police custody, witnesses said. Other reporters were detained by police and some were roughed up, including one from Taiwan whose hand was injured, they said.

Ambassador Huntsman, a former Republican governor of Utah who will soon leave his job in Beijing, said he had met with several of the reporters who had been detained or otherwise harassed.

This type of harassment and intimidation is unacceptable and deeply disturbing. I am disappointed that the Chinese public security authorities could not protect the safety and property of foreign journalists doing their jobs, Huntsman said in a statement.

I call on the Chinese Government to hold the perpetrators accountable for harassing and assaulting innocent individuals and ask that they respect the rights of foreign journalists to report in China.

Huntsman has sparred with China over rights in the past few weeks, including standing outside a Chinese court to criticize it for rejecting the appeal of an American jailed on industrial spying charges.

The European Union also said it was concerned by the harassment of reporters.

We urge the Chinese authorities to respect the rights of foreign journalists to report freely in China ... and also to ensure their physical safety, its diplomatic mission to Beijing said in a separate statement.

We call on the relevant authorities to clarify the legal basis for the physical obstruction and detention of foreign journalists on Sunday.

Foreign journalists are occasionally harassed or detained in China when covering sensitive stories, though mostly outside of the main cities.