The North Atlantic Treaty Organization called on Russia to withdraw its soldiers and refrain from any other interference in the Crimean peninsula in Ukraine.
The alliance, made up of the United States and 27 other countries, said Russian military action against Ukraine would amount to a breach of international law.
NATO urged both countries to seek a peaceful solution and called for the dispatch of United Nation observers to the region.
While Ukraine is not a member to NATO, the group said it is a “valued partner” and a member of its “Partnership for Peace.” NATO said it would support Ukrainian independence.
“We emphasize the importance of an inclusive political process based on democratic values, respect for human rights, minorities and the rule of law, which fulfills the democratic aspirations of the entire Ukrainian people,” the statement read.
On Monday, Sen. Chris MurphyChris MurphySenators eye new sanctions against Iran For Trump and Russia, the fall of Michael Flynn is only the beginning Overnight Finance: Trump's Labor pick withdraws | Ryan tries to save tax plan | Trump pushes tax reform with retailers MORE (D-Conn.), a member of the Foreign Relations Committee, said on MSNBC he hoped the situation could lead to Ukraine eventually becoming part of NATO.
The administration and six other members of the G8 have also announced they are suspending planning for a summit in Russia later this year after thousands of Russian troops had taken, what administration officials call, “operational control” of the peninsula in southern Ukraine, which holds a large Russian-speaking population.
Secretary of State John KerryJohn KerryFormer Obama officials say Netanyahu turned down secret peace deal: AP How dealmaker Trump can resolve the Israeli-Palestinian conflict John Kerry to teach at Yale on global issues MORE on Sunday said Russia could be removed from the G8 and warned of possible asset freezes, visa bans and disruption of trade if Russia did not pull back.
Kerry is planning a trip to the Ukrainian capital of Kiev on Tuesday to meet with the new government there.