Welsh authorities said Wednesday they are responding to "an ongoing incident" after a suspicious package was found at a key factory in the United Kingdom's supply chain for COVID-19 vaccines.

The plant, located in the Wrexham Industrial Estate in Wrexham, Wales, is owned by Indian biotechnology company Wockhardt, who have a partnership with British-Swedeish pharmaceutical giant AstraZeneca to manufacture its COVID-19 vaccine in the U.K.

"Wockhardt UK in Wrexham this morning received a suspicious package to site," the company said in a statement to ABC News. "All relevant authorities were immediately notified and engaged. Upon expert advice we have partially evacuated the site pending a full investigation. The safety of our employees and business continuity remain of paramount importance."

North Wales Police told ABC News in a statement: "We are currently dealing with an ongoing incident on the Wrexham Industrial Estate. The roads are currently closed and we would ask the public to avoid the area until further notice."

ABC News' Guy Davies contributed to this report.

American biotechnology company Regeneron Pharmaceuticals announced Wednesday that its cocktail of two monoclonal antibodies held up in laboratory experiments against new variants of the novel coronavirus first identified in the United Kingdom and South Africa.

Monoclonal antibodies are synthetic versions of our natural antibody defense to infection. They are being studied as a way to both treat and prevent COVID-19 infection, with promising results. But unlike vaccines, which are thought to offer broader protection, some scientists have been worried that this type of therapy would be less effective against newly emerging variants of the virus.

Wednesday's announcement is good news for Regeneron's monoclonal antibody treatment, REGEN-COV, though the data is still preliminary and currently under peer review.

Regeneron scientists as well as researchers at Columbia University in New York City have each independently confirmed that the casirivimab and imdevimab antibody cocktail successfully neutralized both the U.K. and South Africa variants when tested against them, according to a company press release.

REGEN-COV has not yet been tested against another variant that was first identified in Brazil. However, Regeneron said the two-antibody cocktail "is expected to remain similarly potent" based on some resemblance which the Brazil variant bears to the South Africa strain. The company said it is pursuing further confirmatory research.

It's the latest piece of promising news about the efficacy of monoclonal antibodies as treatment for COVID-19. On Tuesday, American pharmaceutical firm Eli Lilly and Company announced that a combination of two monoclonal antibodies, bamlanivimab and etesevimab, was found to be effective in COVID-19 patients at high risk of severe infection, reducing the risk of hospitalization and death by 70%, according to the results of a final-stage trial.

That same day, Regeneron announced its antibody cocktail had shown positive initial results in prophylactic use -- that is, helping ward off COVID-19 in those who may have been exposed to the virus. Regeneron’s chief scientific officer, Dr. George Yancopoulos, said he hopes the drug "may be able to help break this chain" of active infection and transmission.

Last Thursday, Eli Lilly released data showing bamlanivimab may help prevent disease and stop outbreaks among residents and staff of long-term care facilities.

ABC News' Sasha Pezenik contributed to this report.

January is now already the deadliest month of the coronavirus pandemic for the United States.

So far this month, 79,261 people have lost their lives to COVID-19 in the U.S., surpassing December's record 77,124 deaths, according to real-time data compiled by Johns Hopkins University.

December still holds the record for the highest number of diagnosed COVID-19 cases.

ABC News' Ahmad Hemingway contributed to this report.

The official commemoration of the 76th anniversary of Auschwitz's liberation will be held online Wednesday due to the coronavirus pandemic.

The Auschwitz-Birkenau State Museum and Memorial, which is located on the site of the Nazi concentration camp in Oswiecim, Poland, is closed for visitors until at least Jan. 31 under COVID-19 restrictions set by the Polish government.

"Due to the coronavirus pandemic, the commemoration will exceptionally not be held at the Memorial, but in the virtual space," Auschwitz Memorial spokesperson Pawel Sawicki said in a statement Tuesday evening. "The main theme of the 76th anniversary of the liberation will be the fate of children in Auschwitz."

The online events will include testimony from survivors as well as a guided virtual tour of the Auschwitz Memorial, "aimed at enhancing the educational value for visitors from around the globe," according to Sawicki.

Auschwitz, also known as Auschwitz-Birkenau, was a complex of over 40 concentration and death camps run by Nazi Germany in occupied Poland amid the Holocaust during World War II. It was the largest of the Nazi concentration camps and extermination centers. More than 1.1 million men, women and children lost their lives there, mainly Jews, according to information on the Auschwitz-Birkenau State Museum's website.

In January 1945, as Soviet Russia advanced deeper into Nazi-occupied Poland toward the end of the war, Nazi officers organized a forced evacuation of the Auschwitz prisoners. Almost 9,000 prisoners, most of whom were sick or suffering from exhaustion, were deemed unfit to join the death march to Germany. The Nazis intended to kill them all as part of attempts to destroy the evidence of their crimes at Auschwitz, but only managed to murder about 700 Jewish prisoners between the departure of the final evacuation column and the arrival of Soviet forces.

Soviet troops entered Auschwitz on Jan. 27, 1945, a day now commemorated as International Holocaust Remembrance Day, and liberated more than 7,000 survivors, according to the museum's website.