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.

Late Friday evening, the Senate passed a stopgap bill that would fund the Department of Homeland Security for one week. The deadline to fund the department expires at midnight Friday. 

Earlier in the day, the House failed to pass a stopgap bill to fund DHS for three weeks, with conservative Republicans abandoning Speaker John Boehner (R-Ohio) in his attempt to prevent a department shutdown.

It remains to be seen whether the House will pass the latest Senate bill.

The House on Friday failed to pass a stopgap bill to fund the Department of Homeland Security for three weeks, with conservative Republicans abandoning Speaker John Boehner (R-Ohio) in his attempt to prevent a department shutdown. The Senate earlier in the day passed a bill to fund the department that stripped curbs on President Obama's recent executive actions on immigration, which House Republicans oppose.

This is the latest in a long series of humiliating setbacks for Boehner, who has failed time and again to corral his restive caucus on important votes.

The deadline to fund the department expires at midnight. It remains to be seen whether Boehner will conjure up a face-saving Plan B, or allow a vote on the Senate measure, hoping it will pass with a coalition of moderate Republicans and Democrats.

Boris Nemtsov, Russia's former deputy Prime Minister and harsh critic of President Vladimir Putin's regime, has reportedly been shot dead while walking in Moscow near the Kremlin.

Nemtsov, 55, served under Russia's first post-Soviet President Boris Yeltsin in the 1990s, but became a popular figure in opposition politics once Yeltsin's successor, Vladimir Putin, came to power.

Fresh on the heels of the discovery of a supermassive black hole, astronomers have located a medium-sized black hole in the NGC 2276 host galaxy, 100 million light years away.

The black hole is extremely rare, Discovery News reports, and it could be "the missing link in black hole evolution." NASA's Chandra X-ray Observatory and the European Very Long Baseline Interferometry (VLBI) Network found the black hole, thanks to radio waves "from energetic sources in the cosmos," Discovery News notes.

Intermediate-mass black holes are notoriously difficult to find, and the one in question, NGC-2276-3c, is extremely important to astronomers. The black hole has qualities representative of both stellar-sized black holes and supermassive black holes, Andrei Lobanov of the Max Planck Institute for Radio Astronomy told Discovery News, so it "helps tie the whole black hole family together."

The astronomers are researching how NGC-2276-3c reached its host galaxy. They believe the black hole may have formed in a dwarf galaxy before merging with NGC 2276. Studying NGC-2276-3c could help scientists better understand black hole growth and how black holes become supermassive in their respective galaxies.

Even the humble padlock is getting a "smart" upgrade, said John Brandon at Wired. A Utah firm called FÜZ Designs has unveiled a Bluetooth-enabled padlock called Noke (pronounced "no key") that can be opened using mobile devices like iPhones and Android phones. To open the $60 lock, just press on the lock's shackle, which triggers the device to search for a paired phone nearby and unlock. If your phone isn't available, don't worry: Noke, which comes in silver or black, also allows users to program the lock with a backup combination. And if the internal battery dies, a terminal on the lock's underside lets you plug in with a new battery for temporary power. "Much nicer than a bolt cutter, right?"

Leonard Nimoy has died at age 83, and President Obama issued a statement Friday praising Nimoy and his portrayal of Star Trek's Spock.

Here's Obama's statement:

Long before being nerdy was cool, there was Leonard Nimoy. Leonard was a lifelong lover of the arts and humanities, a supporter of the sciences, generous with his talent and his time. And of course, Leonard was Spock. Cool, logical, big-eared and level-headed, the center of Star Trek's optimistic, inclusive vision of humanity's future.

I loved Spock.

In 2007, I had the chance to meet Leonard in person. It was only logical to greet him with the Vulcan salute, the universal sign for "Live long and prosper." And after 83 years on this planet — and on his visits to many others — it's clear Leonard Nimoy did just that. Michelle and I join his family, friends, and countless fans who miss him so dearly today. [The Chicago Sun-Times]

Nimoy suffered from complications due to end-stage chronic obstructive pulmonary disease. His last film role was in 2013's Star Trek Into Darkness.

While fellow Floridian Republican Gov. Jeb Bush reaffirms his commitment to immigration reform, Sen. Marco Rubio is upping his appeal to the conservative base by backing off in his support for the issue.

Rubio elicited laughter from the audience at CPAC during a Q&A session with Fox News' Sean Hannity when he admitted that his support for the 2013 bipartisan comprehensive immigration reform bill "wasn't very popular, I don't know if you know that from some of the folks here."

Changing his tune ahead of a probable 2016 presidential run, Rubio now says that he "gets" that there are millions of people living in America illegally who have not broken any other law, but that he has "learned you can't even have a conversation about that until people believe and know… that future illegal immigration will be controlled."

The Hill reports that while acknowledging the error of his ways on immigration reform, Rubio also touched on the importance of border security.

"You can't just tell people you're going to secure the border, we're going to do E-Verify," Rubio said, "you have to do that, they have to see it, they have to see it working."

WIsconsin Governor Scott Walker (R)'s proposed budget would probably strike most people as a pretty boring read. But Jezebel has discovered "a non-fiscal bombshell" inside the budget: a plan to stop universities from reporting sexual assaults on campus.

The budget, if approved, would cut $300 million from the state's public university system. But just after a section on student tuition bills, Walker's budget asks the state to "delete language related to sexual assault information and reporting." In that section, Walker proposes the state should "delete the requirement that any person employed at an institution who witnesses a sexual assault on campus or receives a report from a student enrolled in the institution that the student has been sexually assaulted report the assault to the dean of students."

If Walker's budget proposal is approved, universities would no longer be required to report their numbers of campus sexual assaults to the Department of Justice. And university employees who witness sexual assault would have no obligation to report the event. The budget also asks the state to delete its requirement that school orientation programs provide information on sexual assault for new students.

The U.S. economy’s third quarter showed the strongest growth (5 percent) in 11 years, but the fourth quarter, not so much.

A report released today by the Commerce Department shows that the economy grew at an annual rate of 2.2 percent, though early estimates pegged that number at 2.6 percent. The harsh winter may have been to blame for the fourth quarter's lackluster performance.

Analysts, however, are hopeful that the sluggish cycle won’t become a trend. Some economists have forecasted a growth rate of 3.1 percent for the year, which would be the best GDP performance since 2005.

If you've always wanted a cereal-flavored doughnut, you're in luck.

Taco Bell's new Cap'n Crunch Delights combine the best part of Cap'n Crunch cereal — the berries — with cream-filled doughnut holes. The result is a bright pink pastry filled with cereal milk-flavored cream.

The company is testing the doughnut holes at stores in Bakersfield, California. If the tests are successful, the doughnuts will hit Taco Bell stores nationwide.