Russia's former president called for hypersonic missiles to be put close to Washington, DC.
Dmitry Medvedev lashed out after US officials said the Ukraine war is not "worthy" of Russians.
Hypersonic missiles are exceptionally fast, and can travel on an unpredictable flight path, making them harder to intercept with traditional air defense systems.
The 405-mile-long Potomac River passes through Washington, D.C., the seat of the US federal government.
On Wednesday, Russia announced that it was sending its Admiral Gorshkov warship, armed with Zircon hypersonic cruise missiles, on a long-range voyage that would pass through the Atlantic Ocean, Indian Ocean, and Mediterranean Sea.
Locations:
США, РФ