Russia has sent over one dozen fighter jets to Belbek military base in the Ukrainian region of Crimea, which it has occupied since its annexation in 2014.
Witnesses told Reuters that they had seen Su-27 and Su-30 fighter jets arrive in the air base on December 22.
The United States, United Kingdom and Lithuania have offered military assistance to Ukraine against the onset of Russian advances.
The US State Department offered to provide an additional US $10 million to support Ukraine’s navy, to protect against what they termed a “dangerous escalation”.
Britain’s defence secretary, Gavin Williamson, visited Odessa in Ukraine and stated the UK's intentions to send a Royal Navy warship into the Black Sea next year due to concerns of Russian aggression.
The deployment of fighter jets to Belbek follows a pattern of escalating tensions which came to a fore when Russia seized three Ukrainian Navy vessels last month, and Ukraine responded by saying it would send out warships into the sea to secure access to their ports, which Ukraine claims are effectively under a Russian blockade.
Russia’s foreign minister Sergei Lavrov stated such a move was would be a “provocation" from Ukraine.
Ukrainian President Petro Poroshenko has responded by noting that Russia has moved "more than 80,000 troops, 1,400 artillery and multiple rocket launch systems, 900 tanks, 2,300 armored combat vehicles” and hundreds of aircrafts to their Ukrainian border.
Williamson stressed the importance of access to the sea for Ukraine maintaining “this isn’t Russia’s sea, this is an international sea.”
Commenting further on the issue he stated:
“What we’ve seen since 2014 is unparalleled level of aggression from Russia towards Ukraine and I don’t think any of us would ever be complacent in relation to it [….] It has to be clear that President Putin’s behaviour and actions aren’t acceptable. The pressure needs to be on President Putin to come to the table and start sorting out the mess he has created through the aggressive actions of his armed forces – that is the solution to this."