Russian President Vladimir Putin is not done in eastern Ukraine, NATO's top commander said on Thursday, cautioning that Russia has been building up supplies on its border with Ukraine and keeping its military options open.

• June 25, 2015

The head of NATO said on Wednesday the alliance would not be forced into a new arms race with Russia but that what he called Moscow's aggression in Ukraine had compelled it to strengthen its defenses.

• June 24, 2015

Military spending by NATO countries is set to fall again this year in real terms despite increased tensions with Russia and a pledge by alliance leaders last year to halt falls in defense budgets, NATO figures released on Monday showed.

• June 23, 2015

European Union foreign ministers extended economic sanctions on Russia until Jan. 31 on Monday, keeping up pressure on Moscow to help resolve the Ukraine conflict.

• June 22, 2015

President Vladimir Putin boasted on Friday that Russia had found the "inner strength" to prevent sanctions causing a deep economic crisis, and told the West to stop using "the language of ultimatums."

• June 19, 2015

A senior U.S. State Department official played down on Thursday an announcement by Russia that it will add more than 40 new intercontinental ballistic missiles to its nuclear arsenal this year.

• June 18, 2015

Russia may toughen its response to sanctions imposed by the European Union over the crisis in Ukraine if the bloc extends its measures against Moscow, a Kremlin aide said on Thursday.

• June 18, 2015

The foreign ministers of Russia and Germany spoke on Wednesday and agreed on the importance of ending fighting in eastern Ukraine immediately, Russia's foreign ministry said.

• June 17, 2015