Media playback is unsupported on your device Media caption BBC's Damian Grammaticas reports on the tension behind Joe Biden's China trip

US Vice-President Joe Biden has begun a trip to China by encouraging people to "challenge the government".

Mr Biden told a group applying for visas to the US that "innovation can only occur where you can breathe free".

His visit is expected to focus on an air defence zone declared by China which covers islands controlled by Japan in the East China Sea.

Earlier Chinese state media warned that he should not repeat "erroneous remarks" about the zone.

Mr Biden told his audience that "children in America are rewarded - not punished - for challenging the status quo".

Media playback is unsupported on your device Media caption Explained: China's air-defence zone

For positive change to come, people needed to "challenge the government, challenge religious leaders," he went on.

The US vice-president then attended an official welcome ceremony in Beijing's Great Hall of the People where he met China's Vice-President Li Yuanchao, and said China and the US should expand practical co-operation and deliver results.

Later Mr Biden met the Chinese President, Xi Jinping, and will also meet Premier Li Keqiang.

Analysis Joe Biden's diplomatic skills will be tested in Beijing, as he attempts to quell regional tensions over China's new Air Defence Identification Zone. So far, he appears to be giving China room to explain its intentions behind its seemingly sudden announcement of the new zone. When meeting Washington's allies in Tokyo, Mr Biden stopped short of calling on China to reverse its declaration. Instead, the US vice president said he was deeply concerned by China's actions, leaving his senior aides to proclaim that Beijing's move was a provocative act.

On Thursday he will visit China's leadership compound, known as Zhongnanhai.

Flight zone row

Mr Biden's visit to Asia has been dominated by a row over China's newly declared air zone, which has lead to rising tension in the region.

He had arrived from Tokyo, where he reaffirmed the US alliance with Japan.

While in Tokyo, Mr Biden said he would raise concerns over China's new air zone "in great specificity" during meetings with China's leaders.

Mr Biden and Mr Xi are said to enjoy a relatively close relationship.

China announced a new Air Defence Identification Zone (ADIZ) last month, and said aircraft flying through the zone must follow its rules, including filing flight plans.

The ADIZ covers islands claimed and controlled by Japan, and a submerged rock claimed by South Korea.

The US, Japan and South Korea have rejected China's zone, and flown undeclared military aircraft through the ADIZ.

Chinese media reaction Chinese state media have been calling on the US to refrain from supporting Japan over the ADIZ row. Several papers picked up on the fact that Mr Biden did not issue a joint statement with Japan calling on China to revoke the zone. "Biden's statement [on the zone] was relatively vague on the whole," said the Global Times. China Daily said Mr Biden must be told that "it is Japan that has unilaterally changed the status quo... China is just responding to Japanese provocations". Meanwhile, Xinhua news agency urged the US to "stop indulging Japan's recklessness" and restrain Tokyo. China media: Joe Biden in Asia

On Friday, China scrambled fighter jets to monitor US and Japanese planes flying in the area.

Tokyo has told its national carriers not to file flight plans with the Chinese side when transiting the zone, but on Friday the US said it expected its carriers to "operate consistent with Notams [Notices to Airmen] issued by foreign countries".

This did not indicate "US government acceptance of China's requirements for operating in the newly declared ADIZ", the state department said.

Speaking in Tokyo on Tuesday, Mr Biden said the US was "deeply concerned by the attempt to unilaterally change the status quo in the East China Sea."

'Taking sides'

On Wednesday, Chinese state media criticised Mr Biden's comments.

"Washington has obviously taken Japan's side," state-run newspaper China Daily said in an editorial.

"If the US is truly committed to lowering tensions in the region, it must first stop acquiescing to Tokyo's dangerous brinkmanship," it said, adding that Mr Biden should not simply repeat the US's "previous erroneous and one-sided remarks.

Chinese defence ministry spokesman Geng Yansheng said this week that the zone "is not aimed at any specific country or target, and it certainly does not constitute a threat towards any country or region."

China's military is "fully capable of exercising effective control" over the zone, Mr Geng added.