White House Press Secretary Jay Carney says the Obama administration is "appalled" by the violence in Ukraine.
For the time being, President Barack Obama has assigned the Ukraine problem to Vice President Biden, CBS News chief White House correspondent Major Garrett reported from Toluca, Mexico, where the president will travel Wednesday for a summit.
Biden has called Ukrainian President Vicktor Yanukovich three times since Jan. 23, with the same message each time -- government forces must pull back and de-escalate tensions that have led to violence.
That hasn't happened and concern is rising in the White House and in European capitals. Street fighting in Kiev doesn't directly influence or affect U.S. economic or political interests in the region, but the tug-of-war over Ukraine's future does -- at least broadly. Ukraine had been trending toward democracy and closer ties with the West, but Russian president Vladimir Putin has largely reversed those trend lines with economic incentives to the Yanukovich government -- one that many of those street protesters believe is not only oppressive, but thoroughly corrupt.
The U.S. and European countries are now actively considering tougher economic sanctions -- a message Biden delivered by phone to Yanukovich Tuesday.
President Obama arrives in Toluca Wednesday and is not expected to address Ukraine in his opening summit remarks, preferring to focus on trade, investment and energy talks with his counterparts from Mexico and Canada.