Mr. Obama said the sanctions will have an impact on Russia's financial, energy and defense sectors. He said they'll increase Moscow's political isolation and foist additional economic costs on the country.
"I have said from the very beginning of this crisis that we want to see a negotiated political solution that respects Ukraine's sovereignty and territorial integrity," the president explained in a statement. "Together with G-7 and European partners and our other Allies, we have made clear that we are prepared to impose mounting costs on Russia. We are implementing these new measures in light of Russia's actions to further destabilize Ukraine over the last month, including through the presence of heavily armed Russian forces in eastern Ukraine."
The U.S. penalties will be coupled with a new round of European Union sanctions announced Thursday in Brussels. The U.S. and the EU will both disclose the full details Friday.
The latest sanctions from the West come despite a cease-fire reached last week between Ukraine and pro-Russian separatists.
"We are watching closely developments since the announcement of the ceasefire and agreement in Minsk," the president said in his statement, "but we have yet to see conclusive evidence that Russia has ceased its efforts to destabilize Ukraine."
Mr. Obama said if Russia follows through with its commitments to help end the crisis, the sanctions can be rolled back. Otherwise, he added, they'll be increased.
"The international community continues to seek a genuine negotiated solution to the crisis in Ukraine," he said. "I encourage [Russian] President Putin to work with Ukraine and other international partners, within the context of the Minsk agreement and without setting unreasonable conditions, to reach a lasting resolution to the conflict."