Obama: Russia must pull back troops from Ukraine border
US President Barack Obama has urged Russia to "move back its troops" on Ukraine's border and lower tensions.
Russia is believed to have massed a force of several thousand troops close to Ukraine's eastern frontier.
Mr Obama told CBS News "Because you are bigger and stronger taking a piece of the country, that is not how international law and international norms are observed in the 21st Century".
- From the section Europe