The United States says it has temporarily suspended "several" bilateral projects with Russia and will hand over funding for the initiatives to Ukraine.
A statement published on the State Department website says the decision was made "in response to recent events."
Washington has repeatedly condemned Russia's annexation of Ukraine's Crimea as illegal and imposed sanctions on Russians linked to the move.
The Obama administration has also warned of further measures.
The State Department statement said the projects being suspended include initiatives planned under the U.S.-Russia Bilateral Presidential Commission, as well as "some cooperative law enforcement activities."
No further details were given.
The statement said funding for the projects would be added to U.S. assistance to Ukraine to support economic reform, combat corruption, and recover stolen assets.