The United States believes the shooting down of the Malaysia Airlines passenger plane marks a further escalation of the Ukraine crisis.

Ukraine expert Janine Davidson of the US Council on Foreign Relations wrote that the "immediate conclusion of this disaster should be the pressing need to dial down tensions in the region."

Speaking about the crash, President Barack Obama was both cautious and direct. Perhaps because of a lack of concrete evidence, he stopped short of blaming pro-Russian forces in eastern Ukraine for the tragedy, which took the lives of 298 people. But he spoke more forcefully about Russia's "steady stream of support" for the rebels.

"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 at a press conference.

Refusal to talk peace

The relationship between the Kremlin and separatists in Ukraine is an issue Vikram Singh of the Center for American Progress said needs to be examined, especially as MH17 appeared to have been brought down by advanced surface-to-air missiles.

"The situation that allowed for these types of weapons to be used against a civilian aircraft exists because of the refusal to take advantage of peace plans offered by the Ukrainian government," he said in an interview with DW.

"It is now up to Russia to help ensure that a fair investigation of the disaster takes place and to promote calm in eastern Ukraine," Singh said.

"At this point, the idea that it is somehow Ukraine's fault that the violence continues is really no longer credible," he added.

'Russia can end this war'

Obama, along with the UN Security Council, called for an immediate ceasefire in Ukraine so a comprehensive investigation of the crash could take place. Singh said an independent investigation would have to include Russia and Ukraine.

The separatists' reaction to calls for a ceasefire will be closely watched. Experts have said that how the pro-Russian forces act now could also indicate their willingness to engage in constructive talks in the future.

"My most hopeful thinking is that it will be such a shock that across the board and that this will lead leaders in Moscow to think, 'We have to tell these separatists forces we are done with supporting you in a violent struggle, we will support you at the negotiating table,' and they will move toward a cease-fire and negotiations," Singh said.

But Russia is not showing any willingness to make concessions. In a heated exchange at an emergency meeting of the UN Security Council, US UN ambassador Samantha Power told her Russian counterpart, Vitaly Churkin, "This war can be ended. Russia can end this war. Russia must end this war."

But Churkin blamed the United States and the Ukrainian government for escalating the situation in eastern Ukraine to the point where such attacks could occur. Russian President Vladimir Putin had made similar statements following the crash.

Experts agreed that the situation is extremely volatile and could spread.

"The conflict is clearly escalating and becoming more dangerous; the risk of civilian casualties and spillover will only increase," Davidson wrote.

More pressure for more sanctions

Should Russia and the separatists stick to their positions, Singh said he expected more sanctions would be put in place. He also said he thought it would be harder for other Western countries not to lend their support to placing more sanctions on Russia.

"I would be very shocked if European countries would continue to be hesitant about additional sanctions having lost their own people who were flying innocently from Europe to Asia," he said.