The United States and its G7 partners are imposing new sanctions against Russia. Existing sanctions have not altered Moscow's posture towards Ukraine, with Russian forces still massed along its borders and a promised truce in eastern Ukraine yet to materialize.
Tensions in Ukraine's eastern territories continue to mount. Pro-Russian militias have detained European observers and seized Ukrainian security officers. Government buildings remain barricaded, and some residents continue to agitate for local autonomy from Kyiv.
Visiting Malaysia, U.S. President Barack Obama said volatility in eastern Ukraine is growing, not receding, and pinned the blame on Moscow.
"Russia has not lifted a finger to help. In fact, there is strong evidence that they have been encouraging the kinds of activities that have been taking place in eastern and southern Ukraine," said Obama.
Administration officials say sanctions targeting Russian President Vladimir Putin's inner circle will be expanded.
"We are going to keep on raising the consequences of Russia rejecting that path towards diplomacy," said Obama.
Some U.S. lawmakers are pressing for even tougher sanctions targeting entire sectors of the Russian economy. But Obama appeared to rule out unilateral measures to punish Moscow.
"We are going to be in a stronger position to deter Putin when he sees that the world is unified and the United States and Europe are unified, rather than [that] this is just a U.S.-Russian conflict," said Obama.
Russia says it is acting to protect ethnic Russians in Ukraine from a new government in Kyiv Moscow considers illegitimate and a threat to Russian interests.
In Kyiv, Ukrainian former prime minister Yulia Tymoshenko applauded tougher sanctions against Russia.
"I believe they will be effective. I would like the strength of these sanctions to be so intensive that [President] Putin will stop the aggression, return to the territory of his own country, and stop destabilizing the world," said Tymoshenko.
Meanwhile, more U.S. soldiers are arriving in Eastern European NATO states for military exercises designed to send a message to Moscow. A U.S. commander said, "Should Lithuania need NATO, I guarantee NATO will be there."