Ukraine crisis: G7 countries discuss action against Russia
25 March 2014 Last updated at 00:17 GMT
Ukraine's interim President Olexander Turchynov says he has ordered the withdrawal of armed forces from Crimea.
Members of the G7 group of industrialised nations are meeting in the Netherlands, where talks have focused on what action to take against Russia.
President Obama said Europe and America were united in imposing a cost on Russia for its actions in Ukraine.
Gavin Hewitt reports.