Tokyo (AFP) - The National Basketball Association won't gag its personnel or apologise over a team executive's tweet that ignited a firestorm in China, commissioner Adam Silver insisted Tuesday, standing firm despite a growing backlash that imperils the league's lucrative Chinese following.

The tweet last Friday by Houston Rockets General Manager Daryl Morey supporting pro-democracy protests in Hong Kong has infuriated Chinese fans and led to broadcasters and sponsors severing ties with the NBA.

But Silver, speaking at a press conference in Japan where the Rockets are playing exhibition games this week, said the world's top basketball league would continue to "support freedom of expression and certainly freedom of expression of the NBA community."

"The NBA will not put itself in a position of regulating what players, employees and team owners say or will not say on these issues. We simply could not operate that way," Silver said in a statement before the press conference.

The NBA has found itself squeezed between Chinese anger, and criticism from US presidential candidates, influential senators, and fans over initial statements by the league seen as kowtowing to authoritarian China.

Silver plans to travel to Shanghai on Wednesday for a pair of NBA exhibition games in China between the Los Angeles Lakers and Brooklyn Nets, saying he hoped to meet with officials to discuss the impasse.

But while expressing "regret" that Morey's comments upset China, Silver said the league is "not apologising for Daryl exercising his freedom of expression."

Earlier Tuesday, China's Communist Party-controlled broadcaster announced that it had shelved plans to broadcast the two pre-season exhibition games in China and was considering more punishments.

"We believe that any comments that challenge national sovereignty and social stability are not within the scope of freedom of speech," China Central Television (CCTV) said on its social media account.

Chinese Internet giant Tencent, which streams NBA games to hundreds of millions of fans in China each year, quickly followed suit.

A number of Chinese actors and singers said they would boycott the two exhibition games.

An associated hashtag, "Several stars quit NBA games", was the most-discussed on China's leading social media platform Weibo racking up hundreds of millions of "reads".

- 'Biggest lesson' -

China's government said Morey's tweet was "wrong".

"How can you have exchanges and cooperate with the Chinese side without understanding the (mindset of) the Chinese people. That's not going to work," foreign ministry spokesman Geng Shuang said at a regular press briefing.

Nets players, executives and NBA China officials were to appear at a publicity event at a Shanghai primary school on Tuesday afternoon, but the league abruptly cancelled it just two hours before it was to start, giving no explanation.

Silver said the NBA "so far" had no plans to cancel other events in China.

The Global Times, a nationalist paper known for communicating the Communist Party's thinking to the world, issued a blunt warning to firms that speaking out on human rights and other issues sensitive to China would cost them market access.

"The problem is that Morey's freedom is at the expense of (the) Rockets' huge commercial interests, which the team is unwilling to give up. It's a paradox with which Americans are grappling," the editorial said.

"The biggest lesson which can be drawn from the matter is that entities that value commercial interests must make their members speak cautiously."

- 'Extremely hot' -

Silver said that Yao Ming, the towering Chinese former Rockets star who now heads the Chinese Basketball Association (CBA), was "extremely hot" over the controversy.

"I am hoping that together Yao Ming and I can find an accommodation," Silver said.

"But he is extremely hot at the moment and I understand it."

The NBA's initial statement on the row seemed to satisfy no one.

An English version said it was "regrettable" that Morey's views had offended China.

A Chinese-language version of the statement went further, saying the organisation was "deeply disappointed by the inappropriate remarks".

In the United States, Democratic presidential candidate Beto O'Rourke, a Texan, called the initial statements an "embarrassment."

Florida Senator Marco Rubio, a Republican, accused the NBA of throwing Morey "under the bus" to "protect (the) NBA's market access in China".

"This is bigger than just the @NBA. It's about #China's growing ability to restrict freedom of expression here in the US," he added in a series of tweets.