China is not allowing U.S. scientists to investigate the origins of the novel coronavirus in Wuhan, where the outbreak first emerged in early January. The investigation aims to learn more about the virus and discover the truth behind the conspiracy theory suggesting that the deadly virus originated in a scientific research lab in the sprawling capital of Central China’s Hubei Province.

At a briefing on Sunday, Trump revealed plans to send a team of scientists to China to probe into the COVID-19 pandemic, which has so far infected more than 890,000 and killed 50,000 in the U.S. Since the pandemic took its toll on the U.S., Trump has been openly critical of China and its poor handling of the crisis.

On Wednesday, Secretary of State Mike Pompeo said China’s move to block U.S. scientists from investigating the origins of the pandemic only demonstrates the country’s lack of transparency and openness. He also echoed Trump’s attacks on the Chinese government, saying the pandemic would not have happened if only Beijing officials did not suppress early reports of the outbreak and immediately informed the World Health Organization (WHO) about the gravity of the coronavirus threat.

“Even today, the Chinese government hasn’t permitted American scientists to go into China, to go into not only the Wuhan Lab but wherever it needs to go to learn about the virus, to learn about its origins,” said Pompeo.

There is a theory that the novel coronavirus responsible for the spread of COVID-19 emerged from a laboratory in Wuhan following an accident. While there is currently no evidence to support the theory, both Trump and Pompeo have alluded to it in recent weeks.

Earlier this April, reports revealed that intelligence agencies were assessing the possibility of the coronavirus emerging from a lab accident. Last Wednesday, Donald Trump promised “a very thorough examination” of events, suggesting that he’s subscribing to the theory.

“I will tell you, more and more, we’re hearing the story,” he said on April 15.

Meanwhile, China has dismissed Trump’s criticisms as an effort to divert public opinion from his incompetent response to the pandemic. In recent months, Trump has been under fire for spewing out confused and contradictory statements about the virus and for being slow-footed in the midst of the crisis.

Reuters