President Obama on Friday condemned the missile attack that downed a Malaysia Airlines passenger jet over separatist-controlled eastern Ukraine as an "outrage of unspeakable proportions" but stopped short of blaming Russia directly for the tragedy.
A day after flaming wreckage and mangled bodies rained down on wheat and sunflower fields near the city of Donetsk, U.S. officials identified a lone American victim, a U.S.-Dutch citizen, among the 298 who perished.
The dead came from at least 11 nations, and included nearly 100 researchers and advocates headed to an international conference in Australia dedicated to combating AIDS/HIV.
Senior U.S. officials said strong indications, including satellite and radar tracking data, showed that the surface-to-air missile was launched from an area controlled by Russian-backed separatists.
The officials said evidence so far indicates the missile was a Russian-made Buk, also known as the SA-11 Gadfly, part of a mobile anti-aircraft system probably supplied by Moscow. The Buk can reach up to 72,000 feet, more than twice the altitude of the Boeing 777 shot down.
The United Nations Security Council, meeting in emergency session, endorsed an international investigation. Obama said Russia, pro-Russia separatists and Ukraine must adhere to a cease-fire to allow a credible international investigation.
"The eyes of the world are on eastern Ukraine and we are going to make sure that the truth is out," Obama said at a White House news conference.
"Evidence must not be tampered with," he said. "Investigators need to access the crash site."
U.S. officials said it's not yet clear whether Russian military personnel were involved, either in training militants to use the technically complex antiaircraft system or actually operating it themselves, although investigators will seek to answer those questions.
But Russia has supplied training, tanks, armored vehicles, rocket launchers and antiaircraft systems to the separatists, according to U.S. intelligence. Pentagon officials said it was unlikely the separatists could have brought down the airliner without Moscow's help.
"The SA-11 ... is a sophisticated piece of technology, and it strains credulity to think that it could be used by separatists without at least some measure of Russian support and technical assistance," Rear Adm. John Kirby, the Pentagon spokesman, said at a news conference.
Kirby said "some separatists have received some training in these vehicle-borne systems. There's no question about that."
It's unclear whether the assailants intended to down a passenger jetliner, or believed they were targeting a Ukrainian military aircraft. In June, separatists shot down a Ukrainian transport plane and a military helicopter. This month, they claimed responsibility for downing a fighter jet and a military cargo plane.
The FBI and the National Transportation Safety Board sent a three-person team to the still-smoldering crash site. Some 30 investigators from the Organization for Security and Cooperation in Europe reached the scene, but officials later said they were stopped by armed militants.
Investigators may seek to determine whether separatists looted SA-11 missiles from Ukrainian military arsenals. U.S. officials said they had no information that forces loyal to the government in Kiev had moved missile launchers to the eastern part of the country.
U.S. intelligence agencies have reached only a preliminary conclusion that pro-Russia militants launched the missile, and have not reached any firm conclusions about Russian involvement, a senior official said.
Obama may have tempered his condemnation of Moscow to avoid pushing Russian President Vladimir Putin, who already faces U.S. and European sanctions and deeper isolation, into a corner. U.S. and European leaders urged him pull back Russian forces and supplies, and to seek a negotiated settlement.
U.S. officials said Obama was considering adding additional economic sanctions on Russia if Putin does not move to de-escalate the crisis. Obama said the crash should be a "wake-up call" for Europe, which has been more reluctant to impose tough penalties.
"There are consequences to an escalating conflict in eastern Ukraine," he said. "It is not going to be localized. It is not going to be contained."
Russian officials and separatist groups have denied any involvement in shooting down the plane, blaming the Ukrainian government instead. Claims by separatist groups to have brought down a Ukrainian military plane, posted on social media in the hours after the attack Thursday, were hastily withdrawn.
The Buk system was developed by the Soviet Union in the 1970s and is still produced by Russian arms producers, including a company sanctioned by the Obama administration the day before the airliner was shot down.
At the U.N., the U.S. ambassador, Samantha Power, highlighted evidence suggesting Russian involvement.
"Because of the technical complexity of the SA-11, it is unlikely that the separatists could effectively operate the system without assistance from knowledgeable personnel," Power said. "Thus we cannot rule out technical assistance from Russian personnel in operating the systems."
Power said separatists were spotted hours before the incident with an SA-11 system close to the site where the plane came down.
"We must stop at nothing to bring those responsible to justice," she said.
The victims included a prominent AIDS researcher, Joep Lange. His death was confirmed by the Kirby Institute at the University of New South Wales in Australia.
The American passenger who died was Quinn Lucas Schansman, who had dual Dutch and U.S. citizenship, according to the White House. A Facebook profile appearing to belong to Schansman indicates he was living in Amsterdam in April and was attending the International Business School at Hogeschool van Amsterdam.
Malaysian officials defended the decision to fly over the region. The Malaysian transportation minister said he believed the crew bore no responsibility for the flight plan.
"The flight path taken by MH17 was approved by the International Civil Aviation Organization and by the countries whose airspace the route passed through," Liow Tiong Lai said at a news conference in Kuala Lumpur. "Fifteen out of 16 airlines in the Assn. of Asia Pacific Airlines fly this route over Ukraine."
The airliner had requested to fly at an altitude of 35,000 feet throughout Ukrainian airspace, but Ukrainian air traffic control had instructed the aircraft to fly at 33,000 feet.
U.S. officials late Thursday extended a ban on American aircraft entering airspace in that region, although Federal Aviation Administration officials noted that U.S.-based commercial carriers had no regular flight routes in the problem areas.
Lawmakers in Congress with both parties were harsher than Obama in their criticism of Russia.
"We have sufficient information to know that responsibility for this heinous international crime rests, in large part, with Russian President Vladimir Putin," said Sen. John McCain (R-Ariz.), who called for more military assistance to Ukraine. "If Russia does not pay a heavy price for its culpability in this tragedy, the United States and Europe will lose all credibility, and we should only expect President Putin to grow more reckless and dangerous as a result."
Sen. Richard J. Durbin of Illinois, the No. 2 Democrat in the Senate, said it was time for Putin to "once and for all rein in his mercenaries" and defuse the crisis in Ukraine that has been "largely of his making."
Times staff writers Brian Bennett, Don Lee and Lisa Mascaro in Washington and Tina Susman at the United Nations contributed to this report.