The COVID-19 pandemic has now killed more than 400,000 people in the United States, according to Johns Hopkins University Coronavirus Resource Center.

The tragic milestone was marked by a solemn nighttime ceremony at the Lincoln Memorial in Washington, D.C., where 400 lights that lined the iconic reflecting pool at the front of the memorial were turned on to honor the lives lost.

The ceremony was led by Joe Biden and Kamala Harris on the eve of their inauguration as the nation's next president and vice-president.

"It's hard sometimes to remember, but that's how we heal. It's important to do that as a nation," the president-elect said in brief remarks.

"For many months, we have grieved by ourselves," said Vice President-elect Harris. "Tonight, we grieve and begin healing together."

The United States leads the world in both the number of fatalities and total infections, with more than 24.2 million confirmed cases. The western state of California on Tuesday became the first in the United States to post more than 3 million total COVID-19 cases.

A story in Tuesday's edition of The New York Times says a new variant of the novel coronavirus has been discovered in California. The Times says there is no evidence the new variant, dubbed CAL.20C, is more lethal than other variants that have been detected around the globe. But one researcher told the newspaper it's possible that CAL.20C is playing a large part in the dramatic surge of new infections that has pushed hospitals in the state to the brink of collapse, especially in Los Angeles and elsewhere in Southern California.

California's mass vaccination efforts have hit a major roadblock. The state's epidemiologist Sunday recommended that providers stop using a batch of the Moderna vaccine after some recipients had to seek treatment for possible severe allergic reactions.

Brazil is also running into problems with its mass vaccination drive. The country has granted emergency approval for vaccines developed by AstraZeneca and Chinese-based Sinovac, but Brazil's domestic biomedical laboratories have not received the necessary ingredients from China in order to produce the vaccines. Officials have blamed bureaucratic issues in China for the shipment delays.

A health worker is inoculated with a COVID vaccine at the Clinicas Hospital in Sao Paulo, Brazil, Jan. 18, 2021.

Meanwhile, Reuters news agency is reporting that the Palestinian Authority will receive its first batch of COVID-19 vaccine later this week.

The Authority ordered Russia's Sputnik VA vaccine after granting it emergency use approval, and hopes to inoculate 50,000 residents by March.

None of the more than 5 million Palestinians living in the West Bank or Gaza Strip have been inoculated, while Israel, which controls the West Bank, has vaccinated more than a quarter of its 9 million citizens.

The Associated Press reported Monday that the first doses of COVID-19 vaccines will be administered in the West Bank and Gaza Strip in the first quarter of the year. Yaser Buzieah, the head of the Palestinian Authority's public health agency, said the Authority will receive the first vaccines through COVAX (COVID-19 Vaccines Global Access Facility) an international alliance led by the World Health Organization aimed at distributing free COVID-19 vaccines to the world's poorest nations.