Ukraine's interior minister claims Russian forces have now taken control of two airports in Crimea.
Eyewitnesses in the regional centre of Simferopol say yesterday.
the group was dressed in the same clothing as those who seized the parliament in Crimea yesterday.
One man in uniform explained to euronews why he is there：
"We want the people of Crimea to understand that we will stay here for a long, long period of time
and that it's a place not only for Russians and Tatars, but also for Ukrainians, Germans, Jews
and they want to live here in peace."
An airport spokesperson said the attackers eventually abandoned their plans and apologised.
But shortly afterwards a military airport near the port of Sevastopol was seized.
There are no reports of any bloodshed or clashes near where the Russian Black Sea fleet has a base.
Ukrainehas described the raid
as an armed invasion in violation of international accords.