Brussels - Arriving for an emergency EU summit in Brussels, Slovenian Prime Minister Janez Janša urged EU leaders to adopt the severest possible sanctions against Russia for invading Ukraine. He also called for assistance to Ukraine's government and its people.

Janša said it was key that the Russian authorities "feel the price they are paying for this aggression is high indeed".

He welcomed Germany's decision to stop the Nord Stream 2 pipeline project as something he believes will decisively change the game. However, he believes a step forward is needed.

"We have woken up to a different Europe, a different world, and we must act in accordance with the new situation," he said.

Asked by a reporter about Ukraine's calls to bar Russia from Swift, the global banking payment system, he said it was one of the decisions that needed to be taken, however a more important decision, which is not up to the EU but rather up to NATO, was to close airspace above Ukraine.

This would give the Ukrainians much better options for defence if Russia is not able to fully control their airspace, said Janša, a defence expert himself who served as defence minister when Slovenia was attacked by the Yugoslav army as it declared independence in 1991.

Janša urged helping Ukraine. "We must support them with humanitarian, economic and military help," said Janša, who wore a tie in the colours of the Ukrainian flag as a sign of support.

Expressing his solidarity with Ukraine, he was hopeful that the Ukrainians will defend themselves, "survive and prevail".

He reiterated that the EU should give Ukraine the prospect of full membership as soon as possible, noting that he and his Polish counterpart Mateusz Morawiecki addressed a letter to the European Council to call for that.