Tensions continue to mount in Ukraine as unidentified masked gunmen blocked two airports in the autonomous republic of Crimea.

The armed men, reportedly belonging to the Russian army, surrounded Belbek Airport (the main international airport of Simferapol) and a military airfield in Sevastopol Friday.  

"I can only describe this as a military invasion and occupation," Ukraine's new Interior Minister Arsen Avakov wrote in a post on Facebook, Al-jazeera reports.

"This is an armed invasion and occupation," Avakov's Facebook post read. "It is a direct provocation of armed bloodshed in the territory of a sovereign state," reports The Wall Street Journal.

However, a spokesperson for Russia's Black Sea Fleet, the large operational-strategic sub-unit of the Russian Navy, denied that their soldiers were blocking the Sevastopol airport. Sevastopol is home to the Black Sea Fleet.

"No divisions of the Black Sea Fleet are in the area of Belbek airport and are especially not blocking the airport...Given the volatile situation evolving in the area of the Black Sea Fleet in Crimea, as well as places where military personnel and their families reside, the base has strengthened its antiterrorism security," the spokesperson said, reports The Wall Street Journal.

According to Avakov, nearly 100 people, who identified themselves as Cossacks, tired breaking the fence of the airport grounds. However, the airport security drove them away. Cossacks are Russian traditionalists that closely work with police.

So far, Russia did not make any comment on the masked gunmen in Crimea.

Meanwhile, reports claim that the ousted and fugitive President of Ukraine, Viktor Yanukovych, was spotted in Moscow, Russia. He said he will hold a press conferenceFriday in the southern Russian city of Rostov-on-Don, reports Voice of America.