Russia appears to have effectively invaded Ukraine as reports indicate Moscow's forces are being deployed across the pro-Russian region of Crimea.

Local reports suggest that Russian troops and regular forces are being mobilised all across the region, where the majority are ethnic Russians. Kiev's caretaker interior minister has said an "armed invasion and occupation" by Moscow is underway.

In a Facebook post, Kiev's caretaker interior minister Arsen Avakov said: "The situation is static, with weapons from both sides. I assess this as an armed invasion and occupation, in violation of all international treaties and norms. It is a direct provocation of armed bloodshed in the territory of a sovereign state."

Although there has been no direct armed confrontation as yet at the airports in Crimea, the presence of Russian troops has heightened the tensions.

Avakov said Kiev intends to solve the fragile situation through diplomatic talks.

According to unconfirmed reports, the Russian troops are blockading the Ukrainian troops from entering Crimea.

The deployment amounts to a direct intervention by Russia. Moscow officials had earlier said Russia will uphold the policy of non-intereference in Ukraine.

Although earlier it was claimed the airports were seized by unidentified armed men, reports have since confirmed they are Russian troops. The soldiers, backed by armoured vehicles, are purportedly being stationed to prevent "extremists" from arriving to Crimea through airports.

As well as the main airport in Crimean capital Simferopol, troops have been deployed in other airports such as Belbek in the pro-Russian region. The road to the airport in Sevastopol, the Russian naval base in the warm water Crimean port on the Black Sea, has also been blocked. Moscow has a substantial military presence at the leased naval base.

"We are here at the airport to ensure general order. We don't want radicals coming on planes from Kiev, from UNA-UNSO [Ukrainian nationalist organisation that is militarily opposed to Russia], people from Ukraine to come here and make trouble," a man who identified himself as Vladimir outside the Simferopol airport told Reuters.

"It was our initiative in order to stop the fire from spreading into Crimea. That's why we don't want radicalism to come here. We don't want fascism in Crimea. We want peace in Crimea."