President Biden's National Security Advisor Jake Sullivan said in a statement on Saturday that the administration is concerned by the World Health Organization's (WHO) probe into the origins of the COVID-19 pandemic.

Why it matters: Sullivan said the administration fears the Chinese government may have intervened or altered the findings of the investigation.

Context: On the first day of his administration, Biden acted to return the U.S. to the WHO. The Trump administration had started a withdrawal from the organization in July 2020.

• WHO teams last month conducted the investigation in Wuhan, China, where the virus first emerged.
• The investigation had been agreed to last May, but it was delayed after Chinese officials withheld authorization to allow the international team's scheduled visit.
• The delay drew a rare rebuke from WHO director-general Tedros Adhanom Ghebreyesus.

The WHO team concluded that it's "extremely unlikely" the virus came from a laboratory accident, and that it most likely jumped to humans via an intermediate species.

• “Our initial findings suggest that the introduction through an intermediary host species is the most likely pathway and one that will require more studies and more specific, targeted research,” said WHO scientist Peter Ben Embarek.

What they're saying: "The mission of the World Health Organization (WHO) has never been more important, and we have deep respect for its experts and the work they are doing every day to fight the COVID-19 pandemic and advance global health and health security," Sullivan said in a statement.

• "But re-engaging the WHO also means holding it to the highest standards. And at this critical moment, protecting the WHO’s credibility is a paramount priority."
• "We have deep concerns about the way in which the early findings of the COVID-19 investigation were communicated and questions about the process used to reach them."
• "It is imperative that this report be independent, with expert findings free from intervention or alteration by the Chinese government. To better understand this pandemic and prepare for the next one, China must make available its data from the earliest days of the outbreak."

The big picture: Going forward, Sullivan said all countries, including China, should be more transparent in order to prevent health emergencies like the coronavirus pandemic and allow other countries to respond to them faster.

The other side: The Chinese Embassy in Washington, D.C., said in a statement the U.S. has in recent years "severely undermined multilateral institutions, including the WHO, and gravely damaged international cooperation on COVID-19."

• So the U.S. should not be "pointing fingers at other countries" who've supported the WHO, the statement added.

Editor's note: This article has been updated with comment from the Chinese Embassy.