The head of the World Health Organization, the U.S. government and 13 other countries on Tuesday voiced frustration with the level of access China granted an international mission to Wuhan — a striking and unusually public rebuke.

The comments came as the team tasked with probing the origins of the coronavirus pandemic issued a report on its roughly month-long visit to the central Chinese city.

The report, obtained by The Washington Post on Monday, offers the most detailed look yet at what happened in the early days of the outbreak, but leaves key questions unanswered and has been overshadowed by concern about Chinese influence.

WHO Director General Tedros Adhanom Ghebreyesus said in a briefing to member states on Tuesday that he expected “future collaborative studies to include more timely and comprehensive data sharing” — the most pointed comments to date from an agency that has been solicitous toward China through most of the pandemic.

He said there is a particular need for a “full analysis” of the role of animal markets in Wuhan and that the report did not conduct an “extensive enough” assessment of the possibility the virus was introduced to humans through a laboratory incident.

The report, officially released Tuesday, concludes that the role of markets is unclear and that the idea it could have leaked from a Wuhan lab does not warrant further investigation.

The United States, Britain, South Korea, Israel, Japan and others issued a joint statement Tuesday expressing concern. “Together, we support a transparent and independent analysis and evaluation, free from interference and undue influence,” it reads.

White House press secretary Jen Psaki said at a news conference that the mission was denied access to crucial data and therefore presented “a partial and incomplete picture.”

China, she said, has “not been transparent, they have not provided underlying data. That certainly doesn’t qualify as cooperation.”

Though neither Tedros nor the joint letter named China directly, the message was clear — and is sure to be met with anger and deflection from Beijing.

Chinese officials did not respond directly to the criticism on Tuesday, but the Ministry of Foreign Affairs issued a statement on the report more generally, saying, “China has always been a supporter for global scientific research on the source of the virus and its transmission routes.”

It added: “Study of origins is also a global mission that should be conducted in multiple countries and localities.”

China has repeatedly defended its handling of the outbreak and praised the work of the mission to Wuhan. “Since the outbreak of COVID-19, how many lies and rumors and lies against China have been told by certain politicians, leaders and lawmakers in the U.S. and Europe, including those about China’s lab leak and making of the virus?” spokesperson Hua Chunying asked rhetorically at a regular news briefing on Tuesday.

“When some on the U.S. side pointed fingers at our laboratory in Wuhan, we openly invited the WHO mission for a visit and provided full cooperation. We have also given media access to foreign journalists. But can the U.S. side do the same, and invite international experts and media for a visit in an open and aboveboard manner?”

The terms of reference for the Wuhan mission called for a collaboration between Chinese and foreign scientists, not an independent investigation or audit. Much of the data was collected by Chinese scientists ahead of the visit and then analyzed by the joint team.

Among the key findings is that the market linked to early cases was not necessarily the source of the virus, as some once believed, but may have been the site of an early outbreak as a virus that was circulating in December 2019 spread among stalls selling a variety of seafood and meat. The report notes that the earliest reported case, from Dec. 8, did not have any link to the Huanan market.

The report also recommends further study of the possible path of transmission between species and through frozen food — a once-fringe theory favored by Beijing.

Tedros said Tuesday that mission team members raised concerns to him about access to raw data needed for the report, according to a WHO transcript of his remarks.

“The team reports that the first detected case had symptom onset on the 8th of December 2019. But to understand the earliest cases, scientists would benefit from full access to data, including biological samples from at least September 2019,” he said.

The international team has defended its work, arguing that participants did important research under tough circumstances and calling for patience as scientists slowly sift through clues.

“We have only scratched the surface of the complex set of studies that need to be conducted,” Peter Ben Embarek, the WHO lead, said at a news conference Tuesday.

In interviews, several members of the team stressed that it often takes years, if not decades, to identify the source of new viruses.

The team concluded that it is extremely unlikely that the virus leaked from a lab — a theory many scientists dismiss for lack of evidence but that others are not ready to rule out, especially without additional proof of the means of transmission.

Scientists on the trip made a single visit to the Wuhan Institute of Virology, a facility known for working with bat coronaviruses.

They got a tour of the facility in the presence of staff members and officials, heard about the lab’s safety protocols, and were told the lab was not working with viruses close to SARS-CoV-2, as the novel coronavirus that causes covid-19 is officially known.

The report appears to take assurances from staff members at the lab at face value.

Tedros reiterated Tuesday that “all hypotheses remain on the table.”

“Although the team has concluded that a laboratory leak is the least likely hypothesis, this requires further investigation,” he said, “potentially with additional missions involving specialist experts, which I am ready to deploy.”