A group of experts from the World Health Organization are set to arrive in China on Thursday for an investigation into the origins of the coronavirus pandemic.

China's National Health Commission confirmed the upcoming visit in a brief statement Monday, saying the WHO team would be meeting with Chinese scientists to conduct joint scientific research on the virus's origin. It's unclear exactly where they will be carrying out their research and whether they will travel to the central Chinese city of Wuhan, where the novel coronavirus was first detected in December 2019.

The visit follows negotiations between both sides, with WHO Director-General Tedros Adhanom Ghebreyesus expressing disappointment last week over delays with the probe.

Meanwhile, China marked one year on Monday since confirming its first death from COVID-19, the disease caused by the novel coronavirus. China's National Health Commission has since reported more than 87,000 cases of COVID-19 on the Chinese mainland, including at least 4,634 deaths, though those figures are believed to be much higher.

A new, more contagious variant of the novel coronavirus that was first detected in the United Kingdom has now been discovered in Russia.

The strain, called B117, was confirmed among four Russian citizens who had tested positive for COVID-19 upon returning from the U.K., Russia's chief sanitary doctor, Anna Popova, told reporters Sunday evening.

After being identified in Kent in September, B117 has become prevalent in London and other parts of southeast England.

Last month, Russia joined the growing list of countries to suspend flights from the U.K. amid rising COVID-19 infections and concerns about the highly infectious variant there.

With more than 3.3 million confirmed cases of COVID-19, Russia has the fourth-highest tally of diagnosed infections in the world, followed by the U.K., according to a real-time count kept by Johns Hopkins University.

Russia confirmed 23,315 new cases and 436 additional deaths from the disease on Sunday, according to the country's coronavirus headquarters.

ABC News' Alina Lobzina and Patrick Reevell contributed to this report.

Researchers at Ohio State University's Wexner Medical Center said Wednesday that they've have identified two new variants of the virus that causes COVID-19.

The first variant, which was found in just one person, contains a mutation that's similar to a mutation seen in the variants from the U.K. and South Africa, but it arose independently in the U.S., the researchers said. It is not known if it is more easily transmissible.

The second newly identified variant was found in about 20 patients in Columbus and also arose independently in the U.S., the researchers said. It does not contain any mutations in common with variants identified in the U.K. or South Africa, they said. Scientists said they found cases of this variant with increased frequency during late December, which could imply that it's more easily transmissible, but they emphasized that more studies are needed.

Peter Mohler, a co-author of the study and chief scientific officer at the Wexner Medical Center, said Wednesday, "we’re not ready to overreact," stressing, "this is very normal for a virus to mutate."

ABC News' Sony Salzman contributed to this report.