U.S., EU agree on more sanctions in response to Russia's next moves in Ukraine

The United States and the European Union on Tuesday agreed on more sanctions on Russia in response to what they called its "destabilization" moves in eastern Ukraine.

President Barack Obama joined a meeting between his national security advisor Susan Rice and EU foreign policy chief Catherine Ashton at the White House, in which they discussed the Ukrainian crisis and the ongoing nuclear talks with Iran.

They "agreed on the importance of imposing additional costs on Russia, should it continue its efforts to destabilize Ukraine," the White House said in a statement.

The West is accusing Moscow of being behind the chaos in eastern Ukraine, where pro-Russia militants are occupying a number of cities and towns and engaged in conflict with government troops, as the Kiev authorities have launched an "anti-terror" operation against them, inflicting heavy casualties.

Russia has denied the accusation, and called instead for the Ukrainian troops to be withdrawn and a dialogue between the Kiev government and the militants.

In their meeting, Obama, Rice and Ashton urged Russia to live up to its commitments made in Geneva on April 17 in a meeting with the U.S., EU and Ukraine, including using its influence overthe militants to get them to disarm and engage peacefully in Ukraine's political process.

On Iran, Obama underscored his support for the ongoing negotiations aimed at reaching a comprehensive agreement over the Islamic republic's controversial nuclear program.

The U.S. and EU agreed that "a comprehensive solution must assure the international community that Iran's nuclear program will be exclusively peaceful," the White House said.