At least one American was killed on Malaysia Airlines Flight 17 that went down over eastern Ukraine, President Barack Obama confirmed Friday.

Obama Confirms at Least One American Killed in Malaysia Air Crash

President Obama delivers a statement on the Malaysia Airlines crash over eastern Ukraine, July 18, 2014. (Alex Wong/Getty Images)

Obama said that while the exact circumstances are still being determined, the evidence so far indicates that the passenger plane carrying nearly 300 people was shot down by a surface-to-air missile in a pro-Russia separatist stronghold, likely with Russian support.

“A group of separatists can’t shoot down military transport planes, or they claim shoot down fighter jets, without sophisticated equipment and sophisticated training. and that is coming from Russia,” Obama said.

He called for an immediate cease-fire so that a full “credible international” investigation can begin into the “global tragedy.”

“Obviously, we’re beginning to draw some conclusions given the nature of the shot that was fired,” Obama said. “There are only certain types of anti-aircraft missiles that can reach up 30,000 feet and shoot down a passenger jet.”

He said that the United States does not have a definitive judgment yet, but has increased confidence the missile came from the area controlled by separatists. He added Russia must take some responsibility for that.

“What we do know is that the violence that’s taken place there is facilitated in part, in large part, because of Russian support,” Obama said.

Obama said U.S. officials have been combing through flight records and have identified one person who was definitively either a U.S. citizen or a dual citizen. He identified the passenger as Quinn Lucas Schansman.

Obama said he couldn’t say with “absolute certainty” that there were no additional Americans on board.

“That does nothing to lessen our outrage about all the families, regardless of nationality,” Obama said.

Malaysia Airlines has identified 189 passengers as being from the Netherlands, 44 from Malaysia, 27 from Australia, and other passengers from Indonesia, the United Kingdom, Belgium, Germany, the Philippines, Canada and New Zealand.

About 100 passengers were AIDS researchers traveling to a conference in Australia.

“They dedicated their lives to saving the lives of others and they were taken from us in a senseless act of violence,” Obama said.

Obama spoke by phone with Russian President Vladimir Putin on Thursday as the first reports about the downed plane began to emerge. Obama and Putin were discussing the latest round of economic sanctions against Russian transactions for Russia’s backing of the separatists in Ukraine.

Obama took considerable criticism for attending two Democratic fundraisers in New York after the crash, after also continuing with an event in Delaware to tout his infrastructure plan.

Madeleine Morgenstern contributed to this report.

This post has been updated.