The troop exchange occurs as Ukraine accuses Russia of providing pro-Russian separatists with soldiers and armored vehicles.
At least one Ukrainian military ship was attacked in the Sea of Azov by pro-Russian separatists Sunday.
Ukraine and pro-Russian separatists should discuss "issues of society's political organization and statehood," Vladimir Putin says.
Polish Prime Minister Donald Tusk was appointed Saturday to be the EU's primary representative on the world stage.
Van Rompuy says new sanctions against Russia will be drawn up within a week.
Ukraine President Petro Poroshenko solicited EU support Saturday during discussions of his country's conflict with pro-Russian separatists.
Two wounded majors reportedly refused to accept capture by Russian troops during fighting in the Donetsk region of Ukraine.
"I want to remind you that Russia is one of the most powerful nuclear nations. This is a reality," the Russian president said Friday.
As the crisis in Ukraine worsens, NATO is waiting until next week to decide whether to take any action in the face of an aggressive Russia.
Ukraine is looking to get back on track with its NATO membership, but it's not going to happen overnight, if at all.
Four fighter jets in the Donetsk region have been shot down by Ukrainian separatists, they say.
After more than 20 years as an independent country, Ukraine looks to join NATO. Other ex-Soviet nations already have.
Despite the president's unpopularity, the House Democrats' campaign arm is faring better at fundraising in 2014 than it did in 2010.
The move is sure to rile up Russia, which is under increasing international pressure to end its direct support of pro-Russian separatists in eastern Ukraine.
The company will cut 30 percent of its workforce in a $1.9 billion restructuring, following the twin air disasters that have damaged its brand.
The separatists say they will allow civilians and government troops who lay dow their arms to leave, following a request from Vladimir Putin.
The president says a "military solution to this problem is not going to be forthcoming.”
Russia may have broken the 20-year-old Budapest Memorandum, which protects Ukraine's integrity, and NATO could decide to react.
Falling German investment and trade with Russia is only partly to blame for the economy's recent faltering.
Russian hackers are believed to have hacked JPMorgan Chase and stolen a trove of executives' "sensitive documents."
The international community decides what to do as NATO and Ukraine provide evidence of a Russian incursion into Ukraine.
The currency switch is a protective measure for Russia, since U.S. dollars can be tracked and controlled by American officials.
