1. Health: Coronavirus cases hold steady at 65,000 per day — CDC declares racism "a serious public health threat" — WHO official: Brazil is dealing with "raging inferno" of a COVID outbreak.
2. Vaccines: America may be close to hitting a vaccine wall — Pfizer asks FDA to expand COVID vaccine authorization to adolescents — CDC says Johnson & Johnson vaccine supply will drop 80% next week.
3. Economy: Treasury says over 156 million stimulus payments sent out since March — More government spending expected as IMF projects 6% global GDP growth.
4. Politics: Supreme Court ends California's coronavirus restrictions on home religious meetings.
5. World: Iran tightens COVID restrictions amid fourth wave of pandemic.
6. Variant tracker: Where different strains are spreading.

Iran on Saturday began enforcing tightened COVID restrictions nationwide as the number of coronavirus cases surged.

Driving the news: The country on Friday recorded 22,478 coronavirus cases, its highest single-day total, according to Al Jazeera. Health officials confirmed more than 19,660 cases on Saturday, as the surge in new infections follows last month's Iranian holiday celebrations.

John Kerry, President Biden's special climate envoy, is expected to travel to China next week for meetings with officials aimed at boosting collaboration, the Washington Post reported Saturday.

Why it matters: China is the world's largest carbon dioxide emitter and the U.S. is second-largest.

Myanmar security forces killed at least 82 people during anti-coup protests in the town of Bago on Friday, according to the Assistance Association for Political Prisoners monitoring group.

What they're saying: "It is like genocide," Myanmar Now news outlet quoted protester organizer Ye Htut as saying, per Reuters. "They are shooting at every shadow."

Iran said Saturday it's testing a new and advanced nuclear centrifuge to more effectively enrich uranium, AP reports.

Why it matters: The announcement by Iranian President Hassan Rouhani comes as Tehran and Washington hold indirect talks in an attempt to bring the U.S. back into the 2015 nuclear deal.

Belfast authorities said 19 officers were injured Thursday night while attempting to disperse riots between Protestant and Catholic communities in the city, AP reports.

Why it matters: It brings the total number of officers injured amid violence in the city over the past week to 74. Tensions have flared between Protestant and Catholic communities in Northern Ireland over coronavirus restrictions and the fallout of the Brexit trade agreement.

The Chinese government imposed an antitrust fine equivalent to $2.8 billion on tech and e-commerce company Alibaba, the Wall Street Journal reports.

Why it matters: It's a record penalty in the country and a continuation of Beijing regulators' scrutiny on the business empire of founder Jack Ma, who was ordered in December to transform his Ant Group into a financial holding company overseen by China’s central bank.

Brazil is facing a "raging inferno of an outbreak," Bruce Aylward, senior adviser to the director general of the World Health Organization, warned Friday as the number of coronavirus cases and deaths across the country soars.

Driving the news: The surge, driven in part by relaxed mitigation measures and a more contagious local variant, has overwhelmed the country's health system. Brazil this week confirmed more than 4,000 COVID-19 deaths in a 24-hour period for the first time since the start of the pandemic.

This week's nuclear talks in Vienna "met expectations" but did not assuage U.S. doubts about Iran's willingness to negotiate in good faith over the 2015 nuclear deal, a senior State Department official told reporters on Friday.

The state of play: Iran refused to meet directly with the U.S. but held three days of talks with the nuclear deal's other signatories, while the U.S. — represented in Vienna by Iran envoy Rob Malley — communicated indirectly through envoys, primarily from the European Union.

The State Department issued guidelines on Friday "to encourage U.S. government engagement with Taiwan that reflects our deepening unofficial relationship."

Why it matters: The latest guidance comes amid heightened tensions over Taiwan, whose status is one of the most sensitive political issues between Washington and Beijing.

A tiny British territory on the southern tip of Spain may now be the most protected place on Earth, with all but a sliver of the population vaccinated against COVID-19.

Why it matters: Gibraltar offers the rest of Europe a glimpse of what life might soon be like, if supply shortfalls and vaccine hesitancy can be overcome.

Rep. Elissa Slotkin (D-Mich.) is pushing the Biden administration to designate overseas white supremacist groups as foreign terrorists, Reuters reported Friday.

Why it matters: White supremacist propaganda nearly doubled in the U.S. last year. Social media and conferences have allowed different groups to draw inspiration from one another, according to the Anti-Defamation League.

The United Kingdom's Prince Philip, the Duke of Edinburgh, has died at 99, Buckingham Palace announced Friday.

The big picture: The Duke of Edinburgh, who spent 28 days in the hospital earlier this year, was married to the queen for more than 70 years.

At a party meeting Thursday, North Korean leader Kim Jong-un compared the ills the country currently faces to the severe famines it suffered in the 1990s, according to AP.

Why it matters: Groups monitoring North Korea have not seen signs of mass starvation or a growing humanitarian disaster, but the comparison may underscore how Kim views the country's current economic difficulties.

Threats to Taiwan, the self-governing island only slightly bigger than Maryland, are sending shivers through the global tech industry.

Why it matters: Taiwan is home to 92% of the world's leading-edge chip manufacturing operations and a vital center for producing other tech components, including laptops and PC motherboards.

You've got your COVID vaccine, and the CDC says it's OK to travel this summer, even internationally. But you're likely to find that your overseas options are limited by border restrictions in many countries.

Why it matters: If you don't do your homework before traveling, you could wind up stranded in a foreign airport or quarantined in your hotel room for two weeks.