Schansman held dual U.S.-Dutch citizenship, according to news reports.

According to figures from Malaysia Airlines, 158 of the personnel on board Flight MH-17 were from the Netherlands.

“From the days of our founding, the Dutch have been close friends and stalwart allies of the United States of America, and today I want the Dutch people to know we stand with you shoulder to shoulder in our grief and in our absolute determination to get to the bottom of what happened,” the president said.

“Evidence indicates that the plane was shot down by a surface-to-air missile that was launched from an area that is controlled by Russian-backed separatists inside of Ukraine,” Obama said. “We also know this is not the first time a plane has been shot down in eastern Ukraine.”

In the past few weeks, Russian-backed separatists have shot down a Ukrainian Antonov-26 transport plane and a Ukrainian Mi-8 helicopter, and they claimed responsibility for shooting down a Ukrainian Su-25 fighter jet, the president said.

“Moreover, we know these separatists have received a steady flow of support from Russia,” he said. “This includes arms and training. It includes heavy weapons, and it includes anti-aircraft weapons.”

A credible international investigation must happen now, Obama said. “This was a global tragedy. An Asian airliner was destroyed in European skies filled with citizens from many countries. The U.N. Security Council has endorsed this investigation, and we will hold all its members, including Russia, to their word.”

To facilitate that investigation, Russia, pro-Russian separatists and Ukraine must adhere to an immediate cease-fire, the president said.

“Evidence must not be tampered with, investigators need to access the crash site, and the solemn task of returning those who were lost on board the plane to their loved ones needs to go forward immediately,” he continued.

The United States stands ready to provide any necessary assistance, Obama said.

Personnel from the FBI and the National Transportation Safety Board, which has experience in working with international partners on these types of investigations, are on their way to Ukraine, he said.

The immediate focus will be on recovering those who were lost, investigating exactly what happened, and putting forward the facts in what is likely to be an environment filled with misinformation, the president said.

“The eyes of the world are on eastern Ukraine, and we are going to make sure that the truth is out,” Obama noted.

“This outrageous event underscores that it is time for peace and security to be restored in Ukraine,” he added. “For months, we’ve supported a pathway to peace, and the Ukrainian government has reached out to all Ukrainians, put forward a peace plan, and lived up to a cease-fire, despite repeated violations by the separatists — violations that took the lives of Ukrainian soldiers and personnel.”

Time and again, the president said, Russia has refused to take the necessary steps to de-escalate the situation in Ukraine.

“Instead, it has continued to violate Ukrainian sovereignty and to support violent separatists,” he said. “It has also failed to use its influence to press the separatists to abide by a cease-fire. That’s why, together with our allies, we’ve imposed growing costs on Russia.”

Now is a somber and appropriate time for everyone to step back and take a hard look at what has happened, Obama said.

“Violence and conflict inevitably lead to unforeseen consequences. Russia, the separatists and Ukraine all have the capacity to put an end to the fighting,” he added.