Russian Foreign Minister Sergei Lavrov has told his American counterpart, U.S. Secretary of State John Kerry, that sanctions on Russia over the annexation of Crimea are "unacceptable" and "will not remain without consequences."
Lavrov and Kerry spoke by telephone Tuesday, hours after Russian President Vladimir Putin signed a treaty designating Ukraine's Crimean peninsula as part of Russia, against the wishes of Kyiv and the West.
Earlier in the day, U.S. Vice President Joe Biden, who was in Poland as part of a swing through Eastern Europe, characterized the move as a "land grab" and said the world is rejecting what he called Russia's "flawed logic" behind the annexation.
Poland's Prime Minister Donald Tusk said the dispute over Crimea presents a security problem to the entire region.
While in Eastern Europe, Biden will also meet with the heads of Estonia, Lithuania and Latvia, all former Soviet republics that share a border with Russia.
Meanwhile, French Foreign Minister Laurent Fabius told reporters that Russia's participation in the Group of Eight economic powers has been suspended. However, other members have not confirmed that statement.
The Group of Seven economic powers -- the seven major industrialized nations of the world, which together with Russia form the Group of Eight -- earlier this month condemned Russia's actions in Crimea and canceled plans for a G8 summit scheduled for the Russian resort town of Sochi in June.
A pro-Russian crowd watches a live broadcast of Russian President Vladimir Putin's speech on Crimea, in Sevastopol, Crimea, Ukraine, March 18, 2014.
City council workers clear a barricade on a road leading to Kyiv's Independence Square, Ukraine, March 18, 2014.
An elderly woman holds a calendar depicting Soviet leader Josef Stalin while watching a broadcast of Russian President Vladimir Putin's speech on Crimea, as thousands of pro-Russian people gathered to watch the address, in Sevastopol, Crimea, Ukraine, March 18, 2014.
Russia's President Vladimir Putin addresses the Federation Council in Moscow's Kremlin, Russia, March 18, 2014.
Police look at portraits of missing political activists and journalists that protesters pasted on the gate of the Crimean Interior Ministry in Simferopol, March 18, 2014.
Members of a "Maidan" self-defense battalion take part in a training exercise at a Ukrainian Interior Ministry base near Kyiv, March 17, 2014.
A Ukrainian serviceman guards a checkpoint near the village of Strelkovo in the Kherson region adjacent to Crimea, March 17, 2014.
Members of a Crimean self-defense unit speak with a motorcyclist waving a Russian flag in Simferopol, Crimea, Ukraine, March 17, 2014.
Armed men, believed to be Russian, dig trenches near the Ukrainian military base in Perevalnoye outside Simferopol, March 17, 2014.
A pro-Russian crowd celebrates in the central square in Sevastopol, Ukraine, March 16, 2014.
People wrapped in Russian flags watch fireworks during celebrations after the preliminary referendum results were announced in Lenin Square in the Crimean capital Simferopol, March 16, 2014.
A woman casts her ballot at a polling station during the Crimean referendum, in Sevastopol, Ukraine, March 16, 2014.