The Biden administration is trying to send billions of dollars of military equipment to Ukraine before President-elect Donald Trump takes office, a move that is proving to be logistically challenging and raising concerns about depleting U.S. stockpiles, reports The Wall Street Journal.

Trump, who spoke with Ukraine President Volodymyr Zelenskyy earlier this week following his decisive victory over Vice President Kamala Harris in the U.S. presidential election, has cast doubt on continued U.S. commitment to Kyiv as the war against Russia drags on more than 2 1/2 years.

He has also made a promise to end the war in Ukraine by Inauguration Day.

According to the Journal, the Pentagon is sending to Ukraine more than 500 interceptors for the Patriot missile defense system and the National Advanced Surface-to-Air Missile System, or NASAMS.

On Friday, the Biden administration said it would send "a small number of contractors" to help Ukraine repair and maintain F-16s and other systems.

"Ensuring these weapon systems remain mission capable is critical for Ukraine's defense against Russian aggression," the Pentagon said in a statement.

Because weapons deliveries take weeks, sometimes months, the U.S. is looking into buying back weapons from other countries to give to Ukraine, according to the Journal. 

According to the Department of Defense, the United States has committed approximately $56.3 billion in security assistance to Ukraine through both presidential drawdown authority and the Ukraine Security Assistance Initiative since the Russian invasion in February 2022.

Still, more than $7 billion in drawdown authority, which allows the president to provide defense items such as ammunition and missiles from DOD's inventories to respond to foreign crises, remains unspent.

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