Confirmed by U.S Vice president. It was shot down.

US confirms MH17 was shot down
MH17 "was shot down" and there "may have been American citizens on board", US vice-president Joe Biden has said in Detroit.
Senior US officials has told the Wall Street Journal and CNN that a surface-to-air missile shot down MH17.
As explained by Barbara Starr on CNN, US intelligence had found a heat signature from "a massive event" and "information from intelligence assets" confirming the use of a surface-to-air missile system.
"Information from intelligence assets that a surface to air missile system … was tracking an object, they believe it was the object. There was at racking of the aircraft from a surface-to-air missile system."
"[US intelligence has] another asset that gives them a heat signature, an infrared heat signature that tells them there was a massive event … they put both of these pieces of information together and concluded that the plane was shot down.
"What they don't know and what they're doing now is putting that trajectory together backwards
"Was it the Russian side of the border? Was it the Ukrainian side of the border? What the launch point was, that remains the big question."