London police arrested at least 155 people during protests against coronavirus lockdown measures Saturday, the Metropolitan Police said.

Driving the news: Protesters, including many who were not wearing masks, marched through parts of London, chanting "freedom" and holding signs that read: "no more lockdowns," per Sky News. The country has been under a national lockdown since Nov. 5.

Germany officially topped 1 million confirmed coronavirus cases on Friday, according to data from Johns Hopkins University.

By the numbers: The country reported 20,819 confirmed cases and 371 deaths on Friday, per JHU.

Wilton Gregory, the archbishop of Washington, D.C., became the first Black American to earn the rank of cardinal on Saturday.

The big picture: His appointment comes during a time in which the country continues to examine the role of race relations, and as the world endures the many-month stretch of the COVID-19 pandemic.

Iran's Supreme Leader Ayatollah Khamenei pledged to retaliate one day after the assassination of Mohsen Fakhrizadeh, the nation's top nuclear scientist.

What he's saying: Khamenei wrote on Twitter Saturday to call on "relevant administrators" to prosecute the "brutal mercenaries" behind the attack and continue the "scientific efforts" of Fakhrizadeh, who Khamenei referred to as a "martyr."

The assassination of Mohsen Fakhrizadeh, the architect of Iran’s military nuclear program, is a new height in the maximum pressure campaign led by the Trump administration and the Netanyahu government against Iran.

Why it matters: It exceeds the capture of the Iranian nuclear archives by the Mossad, and the sabotage in the advanced centrifuge facility in Natanz.

Top scientists at the World Health Organization on Friday called for more detailed information on a coronavirus vaccine developed by AstraZeneca and the University of Oxford.

Why it matters: Oxford and AstraZeneca have said the vaccine was 90% effective in people who got a half dose followed by a full dose, and 62% effective in people who got two full doses. AstraZeneca has since acknowledged that the smaller dose received by some participants was the result of an error by a contractor, per the New York Times.

Longtime Belarusian President Aleksandr Lukashenko has said he will step down after a new constitution comes into force, according to Belarusian state media.

Why it matters: Lukashenko has faced three months of protests following a rigged election in August. He has promised to reform the constitution to reduce the near-absolute powers of the president, but has insisted that his strong hand is needed to see that process through.

It seems hard to believe that 238 days from now — on July 23 — the Summer Olympics will open in Tokyo. But that's still the plan, after the games were postponed a year because of the pandemic.

Driving the news: The Tokyo organizing committee on Friday announced a series of 18 test events (some for operations), to begin in March and run into May, AP reports.

The Iranian ministry of defense issued a statement on Friday confirming the assassination of Mohsen Fakhrizadhe, an Iranian scientist and the architect behind the Islamic Republic’s military nuclear program.

Why it matters: Fakhrizadhe was the head of the Amad project in the Iranian ministry of defense, which focused on developing a nuclear bomb until 2003.

Thailand and the Philippines announced separately on Friday that they secured deals with AstraZeneca to receive supplies of the company's coronavirus vaccine.

The state of play: These announcements come a day after AstraZeneca said the company will likely conduct a new global trial to measure the vaccine's efficacy.