China tells Trump not to link trade to N. Korea

China said Monday the U.S. should not link trade to discussions about North Korea's nuclear program, after President Donald Trump accused Beijing of taking no action on Pyongyang despite profiting from business with America.

"We believe that the North Korea nuclear issue and China-U.S. trade are two issues that are in two completely different domains," Chinese Vice Minister of Commerce Qian Keming told a press briefing, adding the issues "are not related, and should not be discussed together".

"In general, China-U.S. trade, including mutual investment, is mutually beneficial, and both China and the United States have gained great profits from bilateral trade and investment cooperations," he said.

The comments came in response to a question about tweets from Trump Saturday warning that he would no longer allow China to "do nothing" on North Korea, after the hermit state launched its second intercontinental ballistic missile test.

Trump, who is at loggerheads with Beijing over how to handle Kim's regime, has repeatedly urged China to rein in its recalcitrant neighbor, but Beijing insists dialogue is the only practical way forward.

In his critique, Trump linked trade woes with the Asian giant to policy on North Korea, after South Korea indicated it was speeding up the deployment of a U.S. missile defence system (THAAD) that has infuriated China.

"I am very disappointed in China. Our foolish past leaders have allowed them to make hundreds of billions of dollars a year in trade, yet they do NOTHING for us with North Korea, just talk," Trump wrote.

"We will no longer allow this to continue. China could easily solve this problem!"

The president's tweets coincided with a 10-hour bilateral mission that saw U.S. B-1B bombers along with fighter jets from the South Korean and Japanese air forces practise intercept and formation drills.

It was followed Sunday by the successful test of a THAAD missile defence system in Alaska.

China, Pyongyang's main economic and diplomatic ally, opposes any military intervention and calls for a resolution through dialogue.

It has also long argued that the THAAD deployment in South Korea will destabilise the region.

On trade, the United States has blamed the unbalanced relationship -- marked by a trade deficit with China of $309 billion last year -- on Beijing's policies that impede access to their market.

China says Washington's own rules restricting U.S. high-tech exports are partially to blame.