WATCH: White House national security advisor discusses increased aid to Ukraine

The U.S. will send $400 million more in military aid to Ukraine, several U.S. officials said Thursday, amid concerns that financial assistance for the war against Russia could decline a bit if Republicans take control of Congress.

Watch the briefing in the player above.

At the White House, national security adviser Jake Sullivan said that the new aid package would include important air defense contributions.

“This increased air defense will be critical for Ukraine as Russia continues to use cruise missiles and Iranian-made drones to attack critical civilian infrastructure,” Sullivan said.

He did not discuss the funding total, but noted it would include Stinger missiles for the Avenger system.

The additional ammunition and air defense capabilities come as Russian troops began pulling out of the key Ukrainian city of Kherson, in a widening retreat that could mark a turning point in the war.

Kherson is the only provincial capital that Moscow captured, and the Russian withdrawal could allow Ukraine to win back territory in the south that it had lost.

Ukrainian officials acknowledged that Moscow’s forces had no choice but to flee Kherson but remained cautious, fearing an ambush.

Including the latest aid, the U.S. has committed more than $18.6 billion in weapons and other equipment to Ukraine since Russia attacked on Feb. 24.

The new package of aid will be done under presidential drawdown authority, which allows the Pentagon to take weapons from its own stock and quickly ship them to Ukraine, officials said.

Sullivan also spoke about WNBA star Brittney Griner she had been sent to a penal colony to serve her sentence for drug possession.

U.S. officials have for months tried to negotiate the release of Griner and another American jailed in Russia, Paul Whelan. But there have been no overt signs of progress.

Reporters also asked Sullivan about the threat of more nuclear test from North Korea amid President Joe Biden’s visit to Asia next week.

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