US President Barack Obama took a moment out of his summit with the leaders of Mexico and Canada to address the worsening situation in Ukraine:  Obama warned the Ukrainian military to stay out of it, and said the United States would hold the government responsible for further violence.

“There will be consequences if people step over the line,” said Obama, adding, “And that includes making sure that the Ukrainian military does not step into what should be a set of issues that can be resolved by civilians.”

In reality, there’s not a lot the US can do, and it appears to be already doing it.  American immigration authorities issued a visa ban for 20 senior members of the Ukrainian government and others seen as responsible for the violent crackdown in Kiev.  There’s some talk about economic sanctions, but the EU hasn’t fully warmed to that.

US Treasury Secretary Jack Lew said that Ukraine's fundamental problem is that it suffers from an economic crisis and the country should ask the International Monetary Fund (IMF) for help.

“At the core they have an economic crisis and they are going to need to deal with it,” Lew told an economic conference.  But dealing with the IMF is the offer Ukraine President Viktor Yanukovich already rejected, accepting instead a deal with Moscow that infuriated protesters.

Russia is clearly worried about the demonstrations that have united Ukraine’s center-right to the far right in their common revulsion for Moscow.

“Ukraine stands on a very dangerous threshold,” said Mikhail Margelov, chairman of the foreign affairs committee in the upper house of Russia's parliament.  “It's all following the regulation course for a country heading towards civil war.”

And a Ukrainian-Australian group is urging Canberra to get involved.  Stefan Romaniw of the Australian Federation of Ukrainian Organizations told SBS radio that Oz should assist any effort to impose economic sanctions, including freezing the assets of Ukraine officials that might be squirreled in hiding places around the world.