President Barack Obama said Monday that new sanctions on Russian officials will "continue to increase the costs" on its government and that the United States is prepared to impose further sanctions if needed.
"If Russia continues to interfere in Ukraine, we stand ready to impose further sanctions," Obama said in a statement from the White House.
Earlier Monday, the White House announced a series of sanctions targeting a total of eleven individuals involved in the crisis, including aides to Russian President Vladimir Putin and the ousted former president of Ukraine, Viktor Yanukovych.
"We are making it clear that there are consequences for their actions," Obama said.
The president said he will travel to Europe next week for meetings with allies.
"We will continue to make clear to Russia that further provocations will achieve nothing except to further isolate Russia and diminish its place in the world," Obama added.
In a conference call with reporters, one senior administration official called those measures "far and away the most comprehensive sanctions applied against Russia since the end of the Cold War."
On Sunday, residents of Crimea participated in a referendum on a measure to secede from Ukraine and join Russia. The Obama administration said over the weekend that it rejected the results of that vote, charging that it was "administered under threats of violence and intimidation from a Russian military intervention that violates international law."