French President Francois Hollande and Polish Prime Minister Donald Tusk called for "rapid and targeted European sanctions against those leaders responsible for these acts," the Financial Times reported Wednesday. Other European leaders echoed similar sentiments.
Speaking with reporters aboard Air Force One -- as President Barack Obama traveled to Toluca, Mexico, for the North American Leaders Summit -- deputy national security adviser Ben Rhodes said Wednesday Obama will likely address the matter Wednesday in private talks with other leaders, as well as with public comments.
"We have made it clear we would consider taking action against individuals who are responsible for acts of violence within Ukraine," Rhodes said. "We have a toolkit for doing that that includes sanctions."
Rhodes said it would "figure into our calculus" if the Ukrainian government releases prisoners and negotiates with the opposition.
European Commission President Jose Manuel Barroso, who secured a promise from Ukrainian President Viktor Yanukovych last month that there would be no crackdown on protesters, said Wednesday the European Union would begin the process of sanctioning those behind the violence.
"There are no circumstances that can legitimize or justify such scenes," Barroso said.
"We have also made it clear that the EU will respond to any deterioration on the ground," Barroso said. "We therefore expect that targeted measures against those responsible for violence and use of excessive force can be agreed by our member states as a matter of urgency."
Diplomacy was at a stalemate as EU leaders reportedly couldn't reach Yanukovych by phone, the Times said.
Catherine Ashton, the European Union's foreign policy chief, called a meeting of the bloc's 28 foreign ministers in Brussels Thursday to debate targeted sanctions.
"All possible options will be explored, including restrictive measures against those responsible for repression and human rights violations," Ashton said in a statement Wednesday.
Yanukovych upped the pressure on opposition leaders in Ukraine Wednesday, warning them to "immediately disassociate themselves from radical forces which are provoking bloodshed."