(AFP) - The World Health Organization said it would launch an independent review of its response to the coronavirus pandemic as US President Donald Trump renewed his attack on the global body, branding it a "puppet of China".

Washington is locked in an increasingly bitter spat with Beijing over the new coronavirus pandemic and has also taken aim at the WHO, which on Monday kicked off its first ever virtual assembly.

A resolution tabled by the European Union called for an "impartial, independent and comprehensive evaluation" of the international response to the pandemic, which has so far infected nearly 4.8 million people and killed more than 317,000.

WHO Director-General Tedros Adhanom Ghebreyesus acknowledged there had been shortcomings and told the virtual assembly he welcomed calls for a review.

"I will initiate an independent evaluation at the earliest appropriate moment to review experience gained and lessons learned, and to make recommendations to improve national and global pandemic preparedness and response," he said.

"But one thing is abundantly clear. The world must never be the same.

"We do not need a review to tell us that we must all do everything in our power to ensure this never happens again," Tedros said.

A wide range of country leaders and health ministers hailed the WHO's efforts but US health secretary Alex Azar said its "failure" to obtain and provide vital information on COVID-19 had cost lives.

"We must be frank about one of the primary reasons this outbreak spun out of control: there was a failure by this organisation to obtain the information that the world needed, and that failure cost many lives," Azar said in a video address to the WHO's main annual meeting.

- 'Puppet of China' -

Washington has suspended its funding to the health body, accusing it of being too close to Beijing, and covering up and mismanaging the pandemic.

"In an apparent attempt to conceal this outbreak, at least one member state made a mockery of their transparency obligations, with tremendous costs for the entire world," said Azar, pointing the finger at Beijing.

The outbreak, which emerged in China late last year, has killed and infected more people in the United States than in any other country by far.

Later Monday, President Donald Trump confirmed he was considering slashing or cancelling US support for the WHO because "we're not treated right".

"They're a puppet of China, they're China-centric to put it nicer," he said at the White House.

"They gave us a lot of bad advice."

Trump has accused the WHO of blindly taking the word of China, where the SARS-CoV-2 virus was first detected.

Critics say Trump, who had earlier praised China's response, is trying to divert attention from his handling of the pandemic in the United States, which has suffered by far the highest death toll.

The annual World Health Assembly (WHA) has this year been trimmed from the usual three weeks to just two days, and is focusing solely on the pandemic.

- 'Contradictory strategies' -

UN Secretary-General Antonio Guterres told the assembly the COVID-19 crisis was a "wake-up call".

"Deadly global threats require a new unity and solidarity," he said.

"We have seen some solidarity, but very little unity, in our response to COVID-19. Different countries have followed different, sometimes contradictory, strategies and we are all paying a heavy price."

The UN head said many countries had ignored the WHO's recommendations.

"As a result, the virus has spread across the world and is now moving into the global South, where its impact may be even more devastating, and we are risking further spikes and waves," Guterres said.

Protecting developing countries was not a matter of charity but of enlightened self-interest, he said.

"We are as strong as the weakest health systems," he warned.

Guterres said lessons learned from COVID-19 would be essential for tackling future crises but called for an immediate focus on unity to get through the present emergency.

"Either we get through this pandemic together, or we fail. Either we stand together, or we fall apart."

Despite growing tensions between the world's two largest economies, member states hoped the WHA would adopt a resolution aimed at fashioning a joint response, including commitments on equitable access to potential treatments and vaccines.

Chinese President Xi Jinping voiced support for a joint approach, vowing in his address to make any vaccine his country developed available for all and offered $2 billion in aid.

China currently has five potential vaccines in clinical trials.

French President Emmanuel Macron and German Chancellor Angela Merkel insisted any vaccine must be available to everyone.

© Agence France-Presse