President Barack Obama has warned the Russian annexation of Crimea is "not a done deal" and expressed concern about the Kremlin's territorial ambitions in the region.
Speaking at the Hague, President Obama said the US rejected the "notion that a referendum sloppily organised over the course of two weeks" would "be a valid process" and the West does not recognise the annexation of the peninsula.
President Obama expressed concern about Russian's territorial ambitions and warned further incursions into Ukraine would be a "bad choice" for President Vladimir Putin to make.
The US president suggested Russia's actions in Crimea indicate weakness, not strength, and the fact that Moscow "felt it had to go in militarily and lay bare these violations of international law indicates less influence, not more".
Obama said Russia is "a regional power" that is threatening some of its immediate neighbours "not out of strength but out of weakness."
He recognised it "would be dishonest to suggest there is a simple solution to what has already taken place in Crimea", where Russian troops have seized military bases consolidating Moscow's control over the peninsula it officially annexed last week.
President Obama described the deployment of Russian troops along the Ukrainian border as "an effort at intimidation" echoing concerns expressed by Ukraine's Foreign Minister, Andriy Deshchytsya, who warned the risk of military intervention remains high.
However, Mr Obama acknowledged that Russia “has a right legally to have troops on its own soil” but suggested further action would trigger a fresh round of sanctions.
Yesterday, leaders of the G7 cancelled a planned G8 summit in Russia in an effort to isolate President Putin until the Kremlin "changes course". Instead, world leaders of G7 nations will now meet in Brussels without Russia in June.
In a statement, the group reiterated their support for Ukraine's sovereignty and territorial integrity and warned the G7 is "ready to intensify" sanctions against Russia's wider economy if Mr Putin does not de-escalate tensions in the region.
So far, the West has abstained from imposing tougher sanctions such as arm embargoes and bans on energy imports, which would affect the heart of the Russian economy.
Russia's Foreign Minister, Sergei Lavrov, said the Kremlin does not "cling" to the G8 format and described it as an "informal club" where no one "hands out membership cards".