A U.S. official says that American intelligence authorities now believe a surface-to-air missile took down the Malaysian passenger plane as it flew over eastern Ukraine Thursday.
The official says the U.S. is still working to determine additional details about the crash, including who fired the missile and whether it came from the Russian or Ukraine side of the border. The official was not authorized to discuss the matter publicly so spoke on condition of anonymity.
The U.S. has sophisticated technologies that can detect missile launches, including the identification of heat from the rocket engine.
The plane was carrying 298 people, which is up from a reported 295 earlier in the day Thursday.
The Ukraine government and pro-Russian separatists who are fighting in that region have both denied responsibility for the strike.
Ukraine's U.N. ambassador says the Malaysian airliner would not have crashed if Russia hadn't given pro-Russian separatists a sophisticated missile system that can hit planes.
Yuriy Sergeyev told The Associated Press in an interview Thursday that Russia bears responsibility for the disaster, along with the separatists, whom he called "terrorists."
The ambassador says that in intercepted phone calls, separatists first thought the plane was a military aircraft. After they went to the site and discovered it was a civilian plane, he says, they responded like "animals" and said the aircraft should have been flying over eastern Ukraine.
The calls haven't been verified.
Sergeyev says about the passenger and crew that "from the ground, it's obvious that all the passengers -- they were killed."
Meanwhile, Russian President Vladmir Putin says Ukraine bears responsibility for the crash of a Malaysian airliner.
A Kremlin statement early Friday said Putin opened a meeting with his economic advisers by calling for a moment of silence over the crash.
Then, he said, "This tragedy would not have happened if there were peace on this land, if the military actions had not been renewed in southeast Ukraine. And, certainly, the state over whose territory this occurred bears responsibility for this awful tragedy."
A global air safety group says an international coalition of countries should lead the investigation of a Malaysia plane shot down over Ukraine.
Normally the country where a crash occurs takes the lead on an investigation. Safety experts say they're concerned that because the plane crashed in area of Ukraine that is in dispute, political considerations could affect the investigation.
Kenneth Quinn of the Flight Safety Foundation said only "an independent, multinational investigation can truly get to the bottom of it without political interference." He said he is concerned about "spoilage" of the crash site and investigators' access to critical evidence like data and voice recorders.
Britain says the U.N. Security Council will hold an emergency meeting Friday morning on Ukraine.
Britain's U.N. Mission said Thursday it requested the meeting and later tweeted that it is set for 10 a.m. Friday.
Ukraine's U.N. Ambassador Yuriy Sergeyev tweeted after Thursday's crash in a rebel-controlled area that "Ukraine will present the evidence of Russian military involvement into the Boeing crash. This crime should be fully investigated."
Click here for video from AP of the fireball when the plane went down.