BREMMER: The Crisis In Ukraine Just Escalated Significantly

The conflict in Ukraine has escalated significantly with the shooting down of a Malaysia Airlines passenger plane carrying nearly 300 people, Eurasia Group president Ian Bremmer tells Business Insider.

All 295 people aboard the civilian aircraft were killed. Ukraine's Interior Minister blamed pro-Russian separatists for shooting down the passenger plane with a Russian-made Buk ground-to-air missile system.

Bremmer said the incident has the potential to significantly destabilize the situation. Here's how:

• Ukraine's new government, led by President Petro Poroshenko, will feel more intensified pressure to conduct military operations to push back pro-Russian separatists in southeastern regions of Ukraine.

• More countries could get involved, and in a broader scope. There could be a new push by the Ukrainian government to get military support from the U.S., which has so far resisted, as well as more non-military aid from the European Union.

• During the months-long conflict, Russia has long asserted its right to intervene on behalf of Russian-speaking citizens. The Pentagon said Wednesday that Russia was again building up its forces along the volatile Russia-Ukraine border.

"Ukrainian government now under much more pressure to remove the separatists by force. There's a better chance that they secure meaningful military support (including weapons) from the US and non-military from the EU," Bremmer wrote in an email to BI.

"But the Russians will deny any involvement and demand protection of the Russians on the ground. Likelihood of escalation has just increased significantly."

The U.S. has long accused the Kremlin of supporting the pro-Russian separatists in the Luhansk and Donetsk regions of eastern Ukraine.

The State Department made mention earlier this week of a "deployment site" in southwest Russia, accusing Russia of continuing to "accumulate significant amounts of equipment" there and saying it had roughly doubled the number of tanks, armored vehicles, and rocket launchers at the location. The State Department said it worried that artillery would continue to flow to the separatists. Furthermore, the State Department claims Kremlin officials are allowing troops from the "Donetsk Peoples' Republic" to establish a recruiting office in Moscow.

Bremmer said the plane crash would likely sink U.S.-Russian relations, which had already been at their worst since the Cold War, to a new modern low.

"They were already at their lowest point since the Cold War," Bremmer said. "They've just taken a significant additional step down."