As the World Health Organisation (WHO) team landed in Wuhan on Thursday to study the cause of the Covid-19 outbreak, China blocked two members of the 13-member international team from travelling to the epicentre of the pandemic after they failed the coronavirus antibody test in Singapore.
The WHO first tweeted that the international team of 13 scientists examining the origins of the virus that causes Covid-19 arrived in Wuhan.
The experts were to begin their work immediately during the two-week quarantine protocol for international travellers.
Later, in a separate tweet, WHO said that two members of that team remain in Singapore after they were "tested positive for IgM antibodies".
IgM antibodies are among the earliest potential signs of a coronavirus infection and false positives are also possible with such tests.
"Two scientists are still in #Singapore completing tests for #COVID19. All team members had multiple negative PCR and antibody tests for COVID-19 in their home countries prior to travelling," the WHO said in a tweet.
"They are being retested for both IgM and IgG antibodies."
IgG is the most common type of antibody found in blood circulation.
At a press conference on Thursday, Chinese Foreign Ministry spokesman Zhao Lijian said the country "will strictly follow the relevant epidemic prevention regulations and requirements, and provide corresponding support and facilities for WHO experts who come to China to carry out international cooperation on tracing the origin of the virus".
Asked about the two scientists denied entry, Zhao would not comment, instructing reports to ask "the relevant authorities."
According to the report, this is the second delay for the WHO team, which was due to arrive in China earlier this month.
The team was blocked from flying there by the Chinese authorities, triggering a rare rebuke from the United Nations (UN).
"I am very disappointed with this news," said WHO Director-General Tedros Adhanom Ghebreyesus. "I have been in contact with senior Chinese officials and I have once again made clear that the mission is a priority for WHO and the international team."
The US has also demanded transparency in WHO operations in China.
The overall global coronavirus caseload has topped 92 million, while the deaths have surged to more than 1.97 million, according to the Johns Hopkins University.
In its latest update on Thursday morning, the University's Center for Systems Science and Engineering (CSSE) revealed that the current global caseload and death toll stood at 92,291,033 and 1,961,987, respectively.
The US is the worst-hit country with the world's highest number of cases and deaths at 23,067,796 and 384,604, respectively, according to the CSSE.
India comes in second place in terms of cases at 10,495,147, while the country's death toll soared to 151,529.