“Ukraine and the United States emphasize that they will not recognize Russia's illegal attempt to annex Crimea,” said the nations in a joint statement after talks at the Nuclear Security Summit in The Hague.
“Crimea is an integral part of Ukraine. The United States will continue to help Ukraine affirm its sovereignty and territorial integrity. As the people of Ukraine work to restore unity, peace, and security to their country, the United States will stand by their side,” the statement added.
The U.S. and European allies have warned Russia not to make further incursions on Ukrainian territory and to allow international monitors in Crimea and begin walks over the disputed area with Kiev. But Russian President Vladimir Putin has shown no signs of backing down, with reports Monday saying that the Kremlin was massing troops near Ukraine's borders in another show of strength.
The U.S. and European Union have enacted targeted sanctions against Russian and Ukrainian officials behind the annexation of Crimea and have vowed to put in place tougher measures targeting Russia's economy if Putin does not stand down.
But finding a consensus on further sanctions will prove difficult for Obama, with European leaders, who are heavily dependent on Russia for energy, fearing economic blowback.
The Senate on Monday advanced an aid package for Ukraine, but that bill faces an uncertain future in the GOP-controlled House, where conservative lawmakers oppose measures that would institute reforms to the International Monetary Fund.
Following the break-up of the Soviet Union, Ukraine dismantled its nuclear arsenal in exchange for security guarantees with both the U.S. and Russia. The U.S. said that Russia’s takeover of Crimea had broken those accords and pledged to work with Kiev to further their commitment to nuclear nonproliferation.
The U.S. is supporting the construction of a nuclear research facility in Ukraine and will also provide additional resources to protect sites with radioactive material and track nuclear materials.