In Washington, President Obama held a crisis meeting with key advisors on Monday night in the White House’s situation room on events in Ukraine.
Afterwards, following talks with Israeli premier Benjamin Netanyahu, Obama warned Moscow the US would turn the economic and diplomatic screw if it did not change course.
“The strong condemnation that it’s received from countries around the world indicates the degree to which Russia is on the wrong side of history on this.
“We are examining a whole series of steps – economic, diplomatic – that will isolate Russia and will have a negative impact on Russia’s economy and its status in the world,” Obama said.
US Secretary of State John Kerry will also seek ways to de-escalate the crisis when he arrives in Kyiv on Tuesday.
One proposal being muted by Washington is for an multilateral organisation to oversee negotiations between Ukraine and Russia.
In addition, Obama said Kerry would offer an economic aid package to Ukraine.