Russia-Ukraine updates: US sanctions Russian military shipbuilder, diamond miner

The Russians are flying an average of 200 sorties, military units, per day, while the Ukrainians are only flying about 10, a senior U.S. defense official told reporters Friday.

The official said much of the airspace above Ukraine is heavily guarded by both Ukrainian and Russian surface-to-air missiles, making air operations risky for both sides, but Russian aircrafts do not have to enter that airspace to do damage.

"You can launch cruise missiles from aircraft from a great distance away. And if your target is relatively close, you don't need to enter the airspace," the official said.

The Ukrainians have 56 functioning fighter jets available to them now and they are only flying them five to 10 hours a day, according to the official.

Noting Russia's vast umbrella of anti-aircraft capability over Ukraine and its larger air force, the official repeated some of the arguments we heard from the Pentagon earlier this week about the relative ineffectiveness of sending more aircraft to Ukraine.

"It makes little sense to us that additional fixed-wing aircraft is going to have somehow solve all these problems," the official said.

The official added, "What they need are surface-to-air missile systems, they need [man-portable air-defense systems], they need anti-armor, they need small arms and ammunition and they need these drones, because that's what they're using with great effect. And so that's what we're focused on."

Ukrainian forces are using drones to "terrific effect," especially against Russian ground movements, according to the official.

"They're trained on how to use them [and] they can fly below radar coverage by the Russians," the official said.

Russian troops have not moved any closer to Kyiv from the northwest since yesterday, still approximately 9 miles from city center. But, the U.S. has seen rear elements move up closer to those advance troops. Russians advancing on the capital from northeast are now 12 to 19 miles out, according to the official.

Mariupol is under increasing pressure on Friday as it is surrounded from the northeast and southwest, and is under heavy bombardment, the official said. But, Ukrainians are fighting back there.

Russians are "closing in on" Kharkiv, but the city is well defended and hasn't been taken yet, according to the official.

The Russians have now launched nearly 810 missiles against Ukraine -- almost half have been fired from within Ukraine using mobile platforms. The rest have been fired from Russia, Belarus, and a small number from the Black Sea, according to the official.

-ABC News' Matt Seyler

Russia's Defense Ministry on Friday claimed it seized Igla portable surface-to-air missile systems that were being supplied to Ukraine.

Igor Konashenkov, a spokesman for the Russian Defense Ministry, said a new batch of these systems was seized by Russian troops in the Kherson region.

Russia said it is working to determine which Eastern European country was supplying them.

"Inspection of the serial numbers of the portable surface-to-air missile systems has now been organized to determine the country that supplied these weapons from Eastern Europe," he said.

Russia claimed it downed three Ukrainian drones on Friday, including 2 Bayraktars.

Russia also claimed it has destroyed 1,067 Ukrainian tanks and other armored vehicles and 121 drones since the start of the operation.

NATO will be holding its scheduled Exercise Cold Response 2022 military exercises in Norway for two weeks starting Monday.

The long-running exercise is held every two years and will involve 30,000 NATO troops, including 3,000 U.S. Marines.

About 220 aircraft and more than 50 ships will take part in the exercise.

U.S. forces began training in Norway in December as Marine units conducted cold weather training and planning in the lead up to the exercise.

-ABC New's Luis Martinez

Millions of children inside Ukraine and those fleeing to neighboring countries are at risk of hypothermia, hunger and death, as temperatures could dip below -4 degrees Fahrenheit, non-profit group Save the Children said Friday.

Eastern Europe, including Ukraine, was hit with an "extreme Arctic cold blast" this past week, according to Save the Children

"As temperatures plummet, children who have been forced from their homes are trekking through the brutal cold, with high winds and snow, carrying whatever they could grab before they fled," said Irina Saghoyan, Save the Children’s Eastern Europe director.

-ABC News' Zoe Magee