Obama points the finger at Russia for providing missiles
The United States began building a case yesterday that would pin the blame for the downing of the passenger jet over eastern Ukraine on separatist forces supported by Russia, in a disaster that could dramatically escalate the crisis in Ukraine.
President Barack Obama called for an immediate ceasefire to allow for an unfettered investigation.
Evidence indicates that Malaysia Airlines Flight 17 was shot down by a surface-to-air missile from an area controlled by Russian-backed separatists, Mr Obama said at the White House.
He warned that the incident showed the crisis in Ukraine will not be localised or contained to the region.
"This should snap everybody's heads to attention," he said.
While cautioning that the exact circumstances of the crash were still being determined, Mr Obama pointed his finger at Russia for providing support to separatists that he suggested enabled them to shoot down the plane.
He said such an attack would not be possible without sophisticated equipment and training - "and that is coming from Russia".
"Obviously, we're beginning to draw some conclusions given the nature of the shot that was fired," he said in a stern address.
"There are only certain types of anti-aircraft missiles that can reach up 30,000 feet and shoot down a passenger jet."
Officials from the FBI and the National Transportation Safety Board were on their way to Ukraine to help determine what happened, said Mr Obama.
He warned that evidence must not be tampered with as a United Nations-backed investigation goes forward, and he added: "We will hold all its members, including Russia, to their word in allowing access to the crash."
The president said one American was among the nearly 300 people killed and identified the US citizen as Quinn Lucas Schansman. No other details were available.
At the UN earlier yesterday, US ambassador Samantha Power delivered an extraordinary speech rebuking Russia and noting that the US could not rule out that Russian personnel had assisted separatists in firing a missile.
"Russia can end this war," she said. "Russia must end this war."