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President Biden authorized $200 million in new security assistance to Ukraine, a White House official told Fox News, bringing total defense aid for Ukraine to $1.2 billion in the last year.

Biden's authorization comes after a public disagreement with Poland on sending fighter jets to Ukraine. The U.S. has been flowing weapons into Ukraine but balked at transferring MiGs, saying Russia would see such a move as escalatory.

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Nonetheless, Moscow warned Saturday that it views any weapons deliveries into Ukraine as "legitimate targets."

President Biden speaks at an event in the East Room of the White House, Monday, Feb. 28, 2022, in Washington.  (AP Photo/Patrick Semansky)

Deputy Foreign Minister Sergei Ryabkov said Russia "warned the U.S. that pumping weapons from a number of countries it orchestrates isn’t just a dangerous move, it’s an action that makes those convoys legitimate targets."

Congress this week approved $13.6 billion in additional aid, which includes $6.5 billion for the costs of sending troops and weapons to Eastern Europe and $6.8 billion for refugees and economic aid. Biden plans to sign the spending bill with the additional aid when he receives it next week.

In this image from video provided by the Ukrainian Presidential Press Office and posted on Facebook early Saturday, March 12, 2022, Ukrainian President Volodymyr Zelenskyy speaks in Kyiv, Ukraine. (Ukrainian Presidential Press Office via AP)

In this image from video provided by the Ukrainian Presidential Press Office and posted on Facebook early Saturday, March 12, 2022, Ukrainian President Volodymyr Zelenskyy speaks in Kyiv, Ukraine.  (Ukrainian Presidential Press Office via AP)

The war in Ukraine is in its 17th day, with Ukraine President Volodymyr Zelenskyy saying for the first time Saturday that an estimated 1,300 Ukrainians have been killed by Russia. Zelenskyy also claimed that 500-600 Russian troops had surrendered Friday. 

Pentagon spokesman John Kirby said this week that weapons sent to Ukraine from America and other nations are being "used with great effect."

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Kirby said a defense assessment showed that "adding aircraft to the Ukrainian inventory is not likely to significantly change the effectiveness of the Ukrainian air force relative to Russian capabilities."

Map shows Russia's invasion of Ukraine as of Friday, March 11, 2022.

Map shows Russia's invasion of Ukraine as of Friday, March 11, 2022.  (Fox News)

"Therefore, we believe that the gain from transferring those MiG 29s is low," Kirby said.

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Fox News' Kyle Morris and The Associated Press contributed to this report.