Not only did armed Russian-speaking men seize two airports in Crimea — one military, the other civilian — they have blockaded the roads leading to them. Helicopters have reportedly started coming in and out of one of the airports. Ukraine’s interior minister Arsen Avakov demanded that Russia stop its “military invasion and occupation.”

It’s coming to a head pretty quickly in Ukraine:

Ukraine’s interior minister accused Moscow’s military of blockading an airport near a Russian naval base on Friday and armed men took control of another airport in Ukraine’s Crimean capital of Simferopol.

In a Facebook post, Arsen Avakov called the seizure of the Belbek international airport in the Black Sea port of Sevastopol a “military invasion and occupation.” He added: “It is a breach of all international agreements and norms.”

The Interfax news agency quoted Russian military sources as saying the incident at Belbek airport was intended to stop “fighters” flying in. However, Interfax later quoted a Russian official as saying that no units had approached the airport or blockaded it. NBC News was unable to independently verify either account.

It’s possible that the very large ethnic-Russian population did this on their own. On the other hand, there’s this from NBC’s James Novogrod:

Avakov: 119 armed men arrive Simferopol airport 130am. "They do not hide that they are part of the armed forces of the Russian Federation."

— Jamie Novogrod (@JamieNovogrod) February 28, 2014

And this from ITV’s James Mates:

A soldier at Crimea's Semferipol airport has confirmed to local Channel 1 TV that they are Russian. #Ukraine

— James Mates (@jamesmatesitv) February 28, 2014

Having helicopters coming into the airport after their seizure makes it pretty clear that the operation isn’t Ukrainian anyway. The Kyiv Post has more this morning (via Canopfor):

Avakov said that Sevastopol’s military airport Bilbek at night was blocked off by the military units of the Russian navy, which is based in Sevastopol. He said the airport is surrounded by camouflaged military troops with no identification and carrying guns. He said they do not hide their Russian affiliation.

Inside the airport there is a group of Ukrainian soldiers and border guards, and Ukrainian police troops have surrounded the outer perimeter of the airport. “There have been no armed clashes so far,” he said.

The navy base is Sevastopol is key for the Russian army. Under agreements signed between two countries in 2010, the Russian military can continue to use Sevastopol until 2042, with an option of extending the lease to 2047.

Some 70 kilometers away from the coast, in Crimean capital Simferopol, another airport was taken over by a group of about 100 plain-clothed men, who went inside the airport and onto the runway.

“The interior troops and police pushed these people first into the airport building, and then out of the territory. No weapons were used,” Avakov said.

He said that after the armed men left, a new group of camouflaged men arrived around 1:30 in the morning. They carried automatic weapons and had no markings. Avakov said they entered the building and stayed int he restaurant.

“They are not hiding their affiliation with the army of the Russian Federation,” Avakov said. “Told by the Ukrainian Interior Ministry workers that they are military men and have no right to be there, they answer curtly that they have no instructions to negotiate with you.”

No armed clashes have occurred yet, and Avakov flatly states that the security forces of Ukraine are no match for military units. However, security forces continue to arrive at both airports, waiting outside the barricades for whatever orders may come. The potential for an armed clash rises the more this standoff continues.

There may also be a new standoff in the making:

BREAKING: Ukraine's State Border Guard says coast guard base surrounded by about 30 Russian marines.

— The Associated Press (@AP) February 28, 2014

All of this is a bit ironic after Eli Lake’s report yesterday on the American intelligence estimate of the crisis:

U.S. intelligence estimates conclude that Russia has no intention of invading Ukraine. This, despite the launch of a massive, new Russian military exercise near Ukraine’s border – and despite a series of public warnings from top American and NATO officials, suggesting serious concern about possible Russian military action. …

“The mere fact of the timing when you consider what is going on in Ukraine and you see the sudden nature of the exercise would cause concern,” this official said. “From an intelligence perspective we don’t have any reason to think it’s more than military exercises.”

The assessment is based in part on the fact that not enough medical units have been ordered to accompany the Russian troops to the Ukrainian border to suggest preparation for war, according to one Congressional staffer who has seen intelligence on Russia. This source also said no signal intercepts have detected plans for an invasion.

Er … suuuuuure.

CNN has more from Crimea: