BBC Online :
US President Barack Obama has condemned Russian “aggression” in Ukraine.
Speaking in Warsaw to mark 25 years since the fall of communism in Poland, he hailed Polish democracy as a beacon for neighbouring Ukraine.
“How can we allow the dark tactics of the 20th Century to define the 21st?” he said.
Earlier Obama met Ukraine President-elect Petro Poroshenko, and pledged support for plans to restore peace to the country.
US President Barack Obama: “We stand together now and forever, for your freedom is ours”
Obama called Poroshenko a “wise selection” to lead Ukraine, and said the nation could become a vibrant, thriving democracy if the world community stood behind it.
Poroshenko, a billionaire sweet manufacturer, was elected in May and will be inaugurated as Ukraine’s president on Saturday.
Obama has said he will offer US support as Kiev tries to settle a gas bill with Russian supplier Gazprom, which has threatened to cut supply.
Ukraine’s struggling economy has been in recession since 2012.
During a press conference after meeting Poroshenko, Obama also said the US would help train the Ukrainian law enforcement agencies and military, and provide equipment like night-vision goggles.