Roadblocks have been set up to prevent access to Sevastopol airport in Crimea after armed men began patrolling air hubs in the region.

Ukraine's interior minister has accused Russian forces of being behind the occupations - Arsen Avakov called their presence an "armed invasion".

But Russia's Black Sea Fleet has denied that Russian servicemen are taking part.

The other main Crimean airport, Simferopol, was also occupied by armed men on Friday.

Christian Fraser reports from the road to Sevastopol airport.