Biden says he is deciding whether to send a senior

Russia officially protests US arms sales to Ukraine

The US has agreed for the first time to equip Kyiv with the types of high-powered capabilities that some Biden administration officials considered too great a risk of escalation just weeks ago, including 11 Mi-17 helicopters, 18 155mm howitzer guns and 300 others Switchblade Drones.

A source familiar with the Russian diplomatic note said Moscow was expected to protest the deliveries and it is still unclear if this means Russia will change its behavior in any way. But this person acknowledged that the note could signal a more aggressive Russian stance towards the US and NATO as the war drags on.

A government official told CNN the Russian statement shows how effective US arms sales to Ukraine have been. The official indicated that the Russians are also concerned about the recent announcement, which includes more sophisticated and heavier weapons.

Some Biden administration officials believe the diplomatic note shows the Russians are injured, a senior administration official said. This official said the Russians would not have sent this message if they felt they were in a strong spot on the battlefield.

CNN previously reported that the United States believes Russian President Vladimir Putin’s risk tolerance has increased and that he may be ready to take more aggressive action against the US in response to its support for Ukraine.

Asked for comment, another US official said: “We will not be acknowledging private diplomatic correspondence. What we can confirm is that we, along with allies and partners, are delivering billions of dollars worth of security assistance to Ukraine, which our Ukrainian partners are using to extraordinary effect to defend their country against Russia’s unprovoked aggression and appalling acts of violence.”

The first flight from the US carrying the new $800 million aid to Ukraine is expected to arrive in the region in the next 24 hours, according to a senior defense official. The official said the material would be picked up by Ukrainians at the border and brought into the country. The manifest is not disclosed.

Ukrainian President Volodymyr Zelenskyy has for months been pleading with the West for heavier equipment to effectively repel the Russians who invaded Ukraine on February 24. Russia was repulsed in northern Ukraine and its forces ultimately failed to capture the capital, Kyiv.

But Ukrainian and Western officials have since expected Russia to launch a major offensive in eastern Ukraine, which is different terrain and requires different types of weapons.

“It’s the first time we’ve made these available [155mm] howitzers and the rounds they entail, and that reflects the kind of fighting that Ukrainians anticipate here in this narrower geographic area,” Pentagon spokesman John Kirby told reporters on Wednesday, referring to the Donbass region in the eastern Ukraine.

Despite Russia’s protests, the US is showing no signs of slowing down its military support to Ukraine. Pentagon officials met with defense contractors this week to discuss how to increase production of the types of systems and weapons Ukraine needs to continue the fight.

“That [meeting] really focused on the type of systems and weapons that were relevant in the Ukraine war,” Kirby said Wednesday, as well as “the opportunity to expedite and expand some of those production lines due to heavy use on our inventory.”

This story has been updated with additional reports.

CNN’s Barbara Starr contributed to this report.