Leaders of the Group of Seven economies have told Russia “to cease all efforts to change the status” of Crimea.
The G7 also said they would not recognise the outcome of a planned referendum there.
The European Commission is a member of the G7.
“We call on Russia to cease all preparations for the annexation of Crimea. it’s simply not possible that one century after the first world war, we see this annexation of one part of a country by another country,” said its president, José Manuel Barroso.
The EU wants to remove tariffs on Ukrainian exports and, along with other international institutions, offered some 11 billion euros in financial assistance.
But those loans and grants can only be accessed once the IMF agrees a longer term aid package with Kiev, in return for major economic reforms.