U.S. intelligence agencies said a Malaysian airliner flying over Ukraine was shot down by a surface-to-air-missile of unknown origin Thursday. Vice President Joe Biden said it was “blown out of the sky.” The Boeing jetliner had 295 people on board and was flying from Amsterdam to Kuala Lumpur. Ukraine’s foreign ministry blamed pro-Russian rebels who allegedly used the Russian-made Buk missile system.

The Daily Beast's Josh Rogin reports top Democrats in Congress called the incident a “terrorist attack” and “act of war,” adding that Putin may be to blame.

Anna Nemstova reports that the plane’s black box has been sent to Moscow “for investigation.” If rebels were operating a Buk missile system and shot down the plane, they likely couldn't see what they were shooting at, Chris Albritton and Dave Majumdar report. Clive Irving writes commercial aircraft were avoiding Crimea but apparently not eastern Ukraine, assuming that cruising altitude would keep planes safe.

In June, militia representatives said that the People’s Republic of Donetsk (DNR) had taken control of the Buk, a self-propelled air-defense system designed to combat targets at low and medium altitudes.

Earlier today, separatist leader and Russian intelligence official Igor Strelkov posted online “do not fly in our skies,” adding that his forces shot down a plane.

The full translation follows:

In the region of Torez, a AN-26 was just shot down, crashing behind the “progress” mine. They warned: do not fly in “our skies.” And here is the video-proof of the next “aircraft downing.” It fell behind a slagheap. Not in a residential area. Civilians didn’t suffer. And there’s also information about a second downed airplane, supposedly a Su (Sukhoi).

The head of Ukraine’s security services accuses two Russian intelligence officers of involvement in the crash. Ukraine released this video of the alleged Russian conversation:

The Daily Beast translated the audio:

The plane was shot down just now. Group “Minera.” It fell behind Enakievo.

Where are the pilots?

They went to search and take pictures of the shot down plane. It’s smoke there…

How many minutes ago?

Approximately 30 minutes ago

Yes, Major!

So that’s Chernukhinskie shot the plane down. From Chernukhinsky checkpoint. The Kozaks that stand in Chernukhino. The plane fell into pieces in the air near the mine Petropavlovskaia. First “200.” First “200” was found. The civil one.

How is it going?

For sure it’s a civil plane.

Many people there?

F**k yes. The wreckages fell in yards.

What is the plane?

I’m not sure yet. I was not near the main part. I’m looking only where the first bodies fell. There’re wreckages of internal brackets, seats, bodies.

Any weapons?

Nothing. Civil things, medical scraps, towels, toilet paper.

Documents?

Yes. Indonesian student. From Thompson University.

Separatists in Donetsk are reportedly denying involvement in shooting down the plane as well, claiming they don’t have the Buk missile. Their leader, Alexander Borodai, is saying the airliner was shot down by Ukrainian government forces.

Ukrainian President Petro Poroshenko said: “This is not an incident, not a catastrophe, but a terrorist act.”

Russian President Vladimir Putin blamed Kiev for the crash because it was brought down in Ukraine.

RT, Russia’s English-language news channel, wasted no time in spinning the story into a near-conspiracy theory: An aviation “source” told the network that the intended target of the Ukrainian missiles may have been Russian President Vladimir Putin’s plane. Both planes’ routes intersected at the same location and altitude, according to the source, with Putin’s Air Force One flying by at 16:21 Moscow Standard Time and the Malaysian plane passing the same spot at 15:44 Moscow Standard Time.

A YouTube video of the crash shows debris falling from a cloud of black smoke in the sky over Ukraine.

Reports describe a gruesome scene of “almost unspeakable horror” with “bodies everywhere, organs splayed out.” A New York Times reporter observed, “A woman in a black sweater top lay on her back, blood streaming from her face, her left arm raised as if signaling someone. Another victim, naked except for a black bra, lay on the field, her gray hair mixing with the green grasses, one leg broken and her body torn. A young boy, who looked to be around 10 years old, lay on his side in a red T-shirt reading ‘Don’t Panic.’”

The majority of victims onboard the flight were from the Netherlands. Some 154 Dutch, 27 Australians, 23 Malaysians, 11 Indonesians, six Britons, four Germans, and four Belgians were among the passengers. None were American. Several of the people onboard were HIV/AIDS researchers and activists headed to an International AIDS conference in Australia, according to friends and colleagues on Twitter.

In a statement on Thursday, President Obama extended his sympathies: “Our thoughts and prayers are with all the families of the passengers, wherever they call home.” Late Thursday, White House press secretary Joshua Earnest issued a statement calling for an “unimpeded” independent investigation of the crash scene and a cease-fire to ensure the safety of recovery personnel, and offered the assistance of the FBI and NTSB personnel. “While we do not yet have all the facts, we do know that this incident occurred in the context of a crisis in Ukraine that is fueled by Russian support for the separatists, including through arms, materiel, and training,” Earnest said in the statement, urging Russia to “immediately take concrete steps to de-escalate the situation.”

Read The Daily Beast's full coverage of the war in Ukraine here.