Russia fully withdraws from Kyiv region, Ukrainians get drone training in US: Pentagon update Day 42

The Pentagon has been providing daily updates on the U.S. assessment of the Russian invasion of Ukraine and Ukraine's efforts to resist.

Here are highlights of what a senior U.S. defense official told reporters Wednesday on Day 42:

All Russian troops withdrawn from around Kyiv and Chernihiv

The tens of thousands of Russian troops arrayed against Kyiv and Chernihiv have withdrawn north across the borders of Belarus and Russia to consolidate before likely redeploying to eastern Ukraine, according to the senior defense official.

"We are assessing that they have completely withdrawn from Kiev and from Chernihiv," the official said.

But even with the Russian forces, the territory remains treacherous.

"There are some indications that they left behind mines and things like that, so the Ukrainians are being somewhat careful in some areas north of Kyiv as they begin to clear the ground and clear the territory and re-occupy it," the official said.

On Monday, the Pentagon estimated that roughly one-third of the Russian forces apparently originally designated to take the capital remained.

Before the withdrawal, there were about 20 Russian battalion tactical groups (BTGs) consisting of 800-1,000 troops each in the areas north and northwest of Kyiv, and another 20 BTGs near Chernihiv, according to the official.

While the U.S. hasn't yet seen these troops redeploy elsewhere in Ukraine, it's likely to happen soon, according to the official.

"Our assessment is that they won't want to spend too much time on refit and resupply because they have made a very public show of saying that they're going to prioritize their efforts on the Donbas region," the official said.

But the timing will depend on how much work is needed to get the Russian forces back into fighting condition.

"Some of these units have been much more depleted than others, and it's possible that the Russians could combine units to make new BTGs as a result, we just we just don't know," the official said.

Of the roughly 130 BTGs Russia dedicated to the invasion, about 80 are still inside Ukraine, according to the official. More than 30 are already in the Donbas region.

US sending 'urgent' shipment of anti-tank missiles for fight in Donbas

Ukrainian forces are preparing for a major fight in the east as Russia prepares as many as 40 BTGs to join 30 more battalions already in Donbas.

"They're not waiting," the official said. "They are already adapting to increased Russian activity in the Donbas region and doing the best they can."

On Tuesday, the Biden administration authorized a $100 million drawdown package to "meet an urgent Ukrainian need for additional Javelin anti-armor systems," Pentagon press secretary John Kirby said in a statement.

The senior U.S. defense official said this move was specifically to help in Donbas.

"One of the reasons why you saw us describe this $100 million drawdown package last night as an urgent need for Javelins was in fact because of the activity in the Donbas and the Ukrainians wanting to make sure that they're ready for increased Russian activity there," the official said.

Ukrainians get drone training in US

A small number of Ukrainians currently in the U.S. for "professional military education" were pulled aside for a couple days of training on Switchblade drones, which the U.S. is sending overseas as part of its military aid, according to the official.

"Although it's not a very difficult system to operate, we took advantage of having them in the country to give them some rudimentary training on that," the official said. "And there may be some additional rudimentary training while they're here."

The official said fewer than 12 Ukrainians were given this U.S.-based training.

Pentagon blames Russia for nitric acid explosion

The official said the Pentagon is "monitoring" an apparent nitric acid explosion in the Luhansk region, which Russia blamed on Ukraine.

"We've seen the Russians claim that this was a Ukrainian attack on this. We do not believe that is true," the official said. "We do believe that the Russians are responsible, but exactly what they used when they did it, why they did it, what the damage is, we just don't have that level of detail," the official said.

'Premeditated' Russian atrocities in Bucha

"When you see individuals with their hands tied behind their backs and evidence of being shot in the head, that certainly appears to be premeditated," the official said, again calling for Russian war crimes in Ukraine to be investigated.

Long-range strikes shifting east

Russia has now launched more than 1,450 missiles against Ukraine, according to the official. The Pentagon is seeing more airstrikes targeting the east than Kyiv as Russia shifts its overall focus to the Donbas region.