Ukraine's President Viktor Yanukovich is set to return to work on Monday after a period of sick leave, a statement on the presidential website said. Thousands of anti-government protesters have gathered in central Kiev to demand his resignation.
US Secretary of State John Kerry said both US and EU stand with people of Ukraine in their fight to choose partners.
The top US diplomat was due to meet the Ukraine opposition leaders in Munich during a security summit.
"Our message to Ukraine's opposition will be the full support of President Obama and of the American people for their efforts," Mr Kerry said earlier.
The Ukrainian opposition has urged West to help bring a halt to the violence they blame on President Viktor Yanukovich.
Ukraine has experienced difficult days before but few have been so complex or so pivotal.
The Ukrainian government says it is is ready to use all tools available to restore order if violence and unrest continues.
These are difficult days for Ukraine, a country edging toward its second revolution in a decade.