Secretary of State John Kerry on Sunday warned Russia against its military incursion into Ukraine, saying the United States could respond with visa bans, trade penalties, and a boycott of the next G8 summit to be held in Sochi, Russia, in June if Russia does not withdraw its forces. On Face the Nation, Kerry called Russia's deployment of troops to Crimea an "incredible act of aggression," adding that Russian President Vladimir Putin had acted out of "weakness and out of a certain kind of desperation."

"It is really a stunning, willful choice by President Putin to invade another country," Kerry said. "You just don't in the 21st century behave in 19th century fashion by invading another country on completely trumped up pretext."

The U.S., France, Britain, and Canada have already announced they will sit out upcoming preparatory talks ahead of the G8 summit. Jon Terbush

A 37-year-old man suspected of killing three co-workers in Maryland earlier in the day was captured Wednesday evening in Delaware, police said.

Authorities said Radee Labeeb Prince walked into Advanced Granite Solutions in Edgewood, Maryland, shortly before 9 a.m. on Wednesday and shot five people before fleeing. Three were killed, and two remain in serious condition at the University of Maryland Medical Center. The owner of Advanced Granite Solutions said Prince had worked there for four months as a machine operator. After the shooting, Harford County Sheriff Jeffrey Gahler told reporters the incident was "one of the most heinous acts we've ever seen in our county."

Prince is suspected of shooting an additional person less than two hours later in Wilmington, Delaware. Police there said Prince "had beefs" with the victim, who was shot twice and is expected to survive. Prince has an extensive criminal record, with 15 felony and four misdemeanor convictions in Delaware, ABC News reports. Catherine Garcia

President Trump's decision to add Chad to the list of countries on his latest travel ban came as a surprise to people inside the government, primarily because it all came down to a lack of office supplies.

The Department of Homeland Security asked Chad and every other country to submit samples of passport paper so the department could take a close look and see how secure they are, several U.S. officials told The Associated Press. Chad ran out of passport paper and asked if they could send a sample already made up of the same type of passport, but the Department of Homeland Security denied its request for an exemption.

A spokesman for the Department of Homeland Security confirmed that Chad did not send in a recent sample of its passport paper, but said there are other reasons the country made it on the list, primarily that it "does not share public safety and terrorism-related information." Recently, Chad temporarily stopped issuing passports, so that might be the reason why they didn't have any paper hanging around, but it still seemed like an odd reason to put Chad on the list alongside countries like Syria and Libya. Chad is known for its counterterrorism efforts against Boko Haram, and when national security agencies learned that the Department of Homeland Security and the White House wanted to put Chad on the list, without much input from the State Department or Defense Department, they objected but were overruled, officials told AP. Catherine Garcia

The Food and Drug Administration on Wednesday approved a one-time treatment for lymphoma in adults, only the second time a gene therapy for blood cancer has been given the OK in the United States.

This is the first gene therapy approved for adults, and involves removing a patient's T cells, reprogramming them to find and kill cancer cells, then putting the cells back into the patient, The Associated Press reports. The treatment uses the same technology as a gene therapy recently approved in the U.S. for childhood leukemia, and will cost $373,000 per patient, its manufacturer said. Catherine Garcia

Not so fast, Bill O'Reilly.

On Wednesday evening, former Fox News host Bill O'Reilly decided to support his friend Sean Hannity while taking aim at CNN's Jake Tapper, tweeting, "Sean Hannity kicking serious butt in the ratings. Tapper on CNN as low as you can go." Tapper waited just 11 minutes before responding with a brutal correction. "'Low' would be sexually harassing staffers and then getting fired for it — humiliated in front of the world," he tweeted. "Now THAT would be low."

O'Reilly had to praise Hannity's ratings rather than his own because, as Tapper helpfully pointed out, the former O'Reilly Factor host was let go from Fox News earlier this year after The New York Times reported that several women had accused him of sexual harassment, and he paid out millions in settlements. Catherine Garcia

In an interview Tuesday with radio host Charlamagne tha God, rapper RZA confirmed that the actor Russell Crowe once spat on pop singer and rapper Azealia Banks at a party. RZA, a founding member of the Wu-Tang Clan, admitted Crowe's conduct after initially denying the incident occurred.

In October 2016, Banks recounted the incident in a Facebook post, in which she alleged that Crowe spat on her, choked her, and called her the n-word as he kicked her out of a party he was hosting last year. (Banks later deleted the post.) Banks said she had attended the party as RZA's guest and shortly after the incident, she told E! News, "I felt betrayed, I felt humiliated, I felt low. It almost felt like a set-up."

After Banks expressed her disappointment that RZA did not stick up for her at the time, the Wu-Tang Clan founder made his own Facebook post disputing Banks' account of the night and alleging she spent the night "insulting half the room." He wrote: "There was nothing funny about her behavior. I felt a little embarrassed because she was my guest. Still verbal abuse can be tolerated but when it goes physical ... Azealia threatened to cut a girl in the face with a glass, then actually grabs a glass ... Russell blocked the attack and expelled her from the suite."

In Tuesday's interview, however, Charlamagne tha God asked RZA whether Crowe really had physically touched Banks or spat on her. "Look, he spit at her," RZA conceded. The host followed up and asked, "Did you check him at that point? That's a white dude spitting at a black woman, you have to check him." RZA dodged, saying that while Crowe apologized to him, "the night was crazy, bro, and I don't want to relive it. It was super-duper awkward."

Later that day, Azealia Banks called out RZA in an Instagram post, condemning him in graphic terms for talking about her in the media given that he has not apologized to her for the incident. Kelly O'Meara Morales

A computer program called AlphaGo Zero taught itself how to play a strategic game that is far more difficult than chess, Google found in a recent study, a feat both impressive and a little frightening.

Go is an East Asian strategy game, played on a 19-by-19 grid that has unlimited configurations, NPR explains. Researchers at Google's DeepMind lab developed a program last year using databases of known human configurations for the game, which went on to beat the best Go player on the planet, world champion Lee Sedol.

This time around, researchers at DeepMind tried something new. Instead of teaching the program, then called AlphaGo, known human configurations for the game, they let the machine discover them itself, NPR says. Scientists found that the use of human knowledge could actually impose limits on their program, and that starting with a blank slate was much more effective.

The resulting updated program — dubbed AlphaGo Zero — spent three days playing 4.9 million games of Go against itself. Then, AlphaGo Zero beat the original human knowledge-based version 100 games to 0. AlphaGo Zero also discovered configurations that humans have not yet figured out.

While AlphaGo Zero has some far-reaching implications for the future, it remains to be studied whether this "blank slate" concept may be applied to solving complex problems. Read the full published study at Nature, or a more about the story of AlphaGo Zero at NPR. Elianna Spitzer

Rep. Diane Black (R-Tenn.), in an interview with MSNBC's Chuck Todd about rising health-care costs, proposed last week that emergency rooms should be able to turn patients away.

In the interview, Black cited her experience working in health care to explain why mandating that emergency room workers see every patient who comes in is ineffective. "I'm an emergency room nurse," she told Todd on Friday. "There are people that came into my emergency room that I, the nurse, was the first one to see them. I could have sent them to a walk-in clinic or their doctor the next day, but because of a law that Congress put into place ... you took away our ability to say, 'No, an emergency room is not the proper place.'"

Black is seemingly referring to the 1986 Emergency Medical Treatment and Active Labor Act, which banned hospitals from transferring uninsured patients from private to public hospitals. "That crowds the emergency room," Black said of the directive. "It drives the cost of emergencies up." When Todd asked Black if she was advocating a repeal of the law, she replied, "I would get rid of a law that says that you are not allowed, as a health-care professional, to make that decision about whether someone can be appropriately treated the next day, or at a walk-in clinic, or at their doctor."

Black's position is largely unpopular, even among conservatives at the Heritage Foundation, who suggest an "outright appeal" of the 1986 law is "unlikely." Kelly O'Meara Morales