Russian Ship Makes Close Pay to U.S. Ship; Tensions Rising in Ukraine.
PEREIRA: @ THIS HOUR just into the newsroom, a Russian military plane came very close to a U.S. warship in the Black Sea. Barbara Starr is at the Pentagon to give us an idea of what we know -- Barbara?</s>BARBARA STARR, CNN PENTAGON CORRESPONDENT: News just coming here at the Pentagon about this encounter that actually happened on Saturday. A Russian air force SU-24 came very close, made 12 passes over a 90- minute period near the "USS Donald Cook," which is on training and maneuvers in the Black Sea. Of course, this is all about Ukraine. The U.S. Navy has put a ship into the Black Sea to reassure the European allies there that are nervous about Russia's moves about Ukraine. On Saturday, the Russians apparently responded, making those 12 passes alongside the "Donald Cook." We are told the Russian plane didn't fly directly over the deck of the U.S. Navy warship but flew close enough to get the attention, that the ship called the Russians and tried to reach the cockpit and say back off. The Pentagon this morning calling this provocative and unprofessional. No indication that the fighter jet had missiles under its wings but this is the kind of military activity that the U.S. does not like to see, of course, because when forces get too close to each other you can have accidents. You can have miscalculation. You can have misinterpretation. This was just not what the U.S. wants to see right now in this area of such heightened tensions -- Michaela?</s>PEREIRA: Heightened tensions clearly being seen as a provocation. Barbara Starr, thank you so much for that. We want to stay with the situation in Russia now where pro-Russian protesters in Ukraine have taken over a police building. This is the tenth town in eastern Ukraine where they've occupied government buildings. They're ignoring a government deadline to put down their weapons and get out of those buildings or face a major anti-terror operation. While things have been getting rougher on the streets, there's been no major confrontation yet. Our Nick Paton Walsh is in Donetsk. We're curious. I think people are wondering how long this standoff can continue.</s>NICK PATON WALSH, CNN CORRESPONDENT: Well, it seems to be getting worse. I should just give you something we've noticed very strangely here in the city center of Donetsk. Two helicopters, both seemingly military, one certainly an attack helicopter escorting another flew right over the city center. We can only presume their Ukrainian. But of course, that just reminds people quite how on edge this entire region is. We saw this morning a deadline pass which the interim president of Ukraine said the protesters had to give up their weapons and give up the buildings they've been occupying. No indication they're doing that at all. Instead, we heard from Kiev the suggestion perhaps of holding out the possibility that they might consider a referendum on the future of eastern Ukraine, oddly, to be held on the same day as the presidential election. Surely confusing short for voters. But today, we see those protesters moving further towards the buildings, different towns. Two or three more towns today were reporting difficulties. An extremely tense situation here. I've just been to the local regional administration here in Donetsk in the city center. It's clear they're not even expecting a siege from police any more. So Ukrainian police officers walking calmly past. The question here, as we hear this messy response from Kiev, where is the Ukrainian government in all of this -- Carol?</s>PEREIRA: I don't think -- it's actually, Michaela. No problem, Nick. We know, from afar, it's difficult to tell the voices. Not a problem. Great reporting, stay safe. Keep us updated on the situation there in Ukraine. Ahead @ THIS HOUR, back to our top story. Why did search crews work so long to drop the sub into the water to look for flight 370? That's one of your great questions we'll put to one of our experts next.