The downing of a passenger liner in Ukrainian airspace brought immediate condemnation of Russia, which experts said is at least indirectly responsible for the tragedy. And that criticism is likely to increase and come from all over the world.
Malaysia Airlines confirmed that it has lost contact of flight MH17 from Amsterdam on Thursday. Its last known position was over Ukraine's airspace. It was en route from the Netherlands to Kuala Lumpur, Malaysia.
Separately, an adviser to the Ukraine interior minister told AP that a passenger plane carrying 295 people had been shot down in Ukraine.
Adrian Karatnycky, managing partner at Myrmidon Group, a firm that consults investors in Eastern Europe, told CNBC that the facts that are known about the flight—it was cruising at an altitude of 33,000 feet—are a "smoking gun pointing directly to Russian rebels and Russian technology."
Scott Stewart, vice president of tactical analysis at Stratfor, said the plane's west-to-east bearing fits the pattern of other planes the rebels have shot down in the past week. Ukraine is less likely to have brought down the airliner because its radar systems are more sophisticated and would have picked up the plane well before it was shot down.
In June, pro-Russian separatists in Ukraine shot down a Ukrainian army transport craft using an anti-aircraft missile, killing 49. But that plane was coming down to make a landing. Presumably more sophisticated technology would be required to bring down an aircraft at cruising altitude.
Rebel leader Igor Strelkov acknowledged on his Twitter account that his forces brought down the Malaysian plane with a sophisticated surface-to-air missile, though Kennan Institute Director Matthew Rojansky said it could have been a mistake.
In the Tweet, translated from Russian by CNBC, Strelkov said, "We just shot down this plane—it's lying there somewhere by coal mine 'Progress.' We warned you, don't fly in 'our skies.'"
Pro-Russia rebels have demanded previously that "their" airspace be kept clear of traffic. Rebels already claimed responsibility for strikes against two Ukrainian jet fighters on Thursday.
"The Russians have to be held accountable for what has happened today," former U.S. Ambassador to Russia Michael McFaul told CNBC. The White House hit Russia with more severe sanctions Wednesday for its actions in Ukraine, and McFaul said there will probably be increased sanctions if it can't pressure rebels to agree to a ceasefire.
"If the separatists did take (the jetliner) down, it will produce a tremendous amount of international pressure on Russia to stop backing these guys," said Stratfor's Stewart. That pressure will grow exponentially if it's determined that Russia provided the system used to take the plane out of the sky.
The extremely international circumstances of the crash—an Asian airline flying from a euro zone state over Eastern Europe in a U.S.-made, Boeing 777—inevitably brings global attention to the war in Ukraine and how it's being fought.
"It draws attention of the international community to Russian behavior in a new way...as this is an intercontinental, global event," Karatnycky said.
Hedge fund manager and CNBC contributor Tim Seymour added his agreement.
"This is a case where suddenly this has gone outside of Russia and Ukraine to other regional interests," he said.
Speaking at a press conference, President Barack Obama said the U.S. government is working to determine whether any Americans were on the flight.
Frank Gaffney, president of the Center for Security Policy, said it's important to note that there's a chance the plane was not shot down but crashed for some other reason. But he thinks the situation is bad for Russian interests.
"I do think that what we're seeing is a gathering storm. Evidence of very bad actors with very maligned intents," he said.
The events in Ukraine Thursday and the likely fallout to follow come at a very bad time for Russian President Vladimir Putin, whose country was just slapped with severe sanctions less than 24 hours earlier.
On Wednesday, the United States expanded sanctions against Russia for its failure to do enough to quell the conflict in Ukraine. The new measures target several Russian companies, making it harder for them to refinance international loans. Moscow's Micex stock index lost 2.3 percent Thursday, and the ruble hit a one-month low against the U.S. dollar.
U.S. shares, meanwhile, moved decisively lower after word of the plane crash, after hovering near unchanged earlier in the session.
"If it was the rebels, then people would be less surprised—it would be somebody who got some technology that they couldn't handle. If it was the rebels, it would make Putin much more cautious about continuing to overtly support them."
And what's bad for Russia is, by extension, good geopolitically for Ukraine, said Stratfor's Stewart.
"If this was indeed not the Ukrainians (who shot the plane down), it's much to their advantage," he said. "They don't want to do anything to screw themselves, and just ride the momentum."
Ukraine has been fighting a pro-Russian insurgency in the eastern part of the country for about four months. Russia is widely believed to have been supporting the rebels with military equipment and is likely to have used special forces within Ukraine's borders. Russian troops openly seized Crimea, on the Black Sea, from Ukraine in March.
The downing of a commercial aircraft "shows irresponsibility and danger of the type of proxy war Putin has launched...as these are irregular forces mixed with Russian ultra-nationalist fanatics," said Karatnycky of Myrmidon Group.
Ed Daly, director of Global Watch Operations at risk management firm iJet, said Putin will be forced to condemn the attack on Malaysia MH17 if it turns out that rebels did in fact bring the plane down.
"If it was the rebels, then people would be less surprised—it would be somebody who got some technology that they couldn't handle," Daly said. "If it was the rebels, it would make Putin much more cautious about continuing to overtly support them."
Thursday's crash also comes four months after another Malaysian jetliner, Flight 370, disappeared somewhere over the Indian Ocean or South China Sea. That plane has still not been found despite an international search by naval vessels from a dozen countries.
Malaysian Prime Minister Mohd Najib Tun Razak posted on his Twitter page on Thursday that his country will investigate the latest crash.
"I am shocked by reports that an MH plane crashed," he said. "We are launching an immediate investigation."
—Dina Gusovsky, Everett Rosenfeld and Bo McMillan contributed to this report.