"What is happening in the Crimea is a Russian takeover. There's no doubt about it," he said Saturday. "Russian military forces are involved and there has been a local takeover, too, in recent days. They refuse to dialogue with the new government in Kiev. When they have sought to contact Russia in the past several days, they refused to speak with them. So it's an extremely serious situation."
Earlier, writing on his personal Twitter account, Bildt said it was "obvious that there is Russian military intervention in Ukraine. Likely immediate aim is to set up puppet pro-Russian semi state in Crimea."
The strained relations between the Ukraine and Russia have boiled over as the Ukraine accused Russia of sending thousands of troops into Crimea, to help local pro-Kremlin militia on the Black Sea peninsula. Other European countries, namely France, have demanded that Ukraine territorial integrity be respected.
Bildt said the European Union can work toward a peaceful solution through diplomatic means.
"We must ensure that democracy works. It is a major undertaking. [The EU foreign policy chief] Catherine Ashton is heading there on Monday again, to follow up the progress," Bildt told Swedish Radio News. "It is clear that this in one way or another affects relations with Russia. It is inevitable."