A United States senator confirmed that Russian forces have fallen behind their timeline for the Ukrainian invasion, after a classified briefing on the war.

"Just leaving classified briefing on Ukraine crisis," Sen. Chris Murphy, D-Conn., who chairs the Senate Appropriation's Committee's Subcommittee on Homeland Security, wrote on Twitter. He shared "a few takeaways," including "Confirmation that the Russians have fallen behind their timeline. Ukrainian resistance has been fierce and there have been multiple Russian equipment and logistics failures."

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Murphy went on to note that the Department of Defense and the Department of Homeland Security "are pressing hard for Congress to end the continuing resolution and get a budget passed," in order to make national security agencies "nimble enough to support Ukraine."

Presidents Biden and Putin

Presidents Biden and Putin (Chip Somodevilla/Getty Images |   Mikhail Svetlov/Getty Images)

While the president releases his preferred budget and Congress passes continuing resolutions to fund the government, Congress has not passed a full budget on time since the 1990s.

"The ability to keep supply lines running to Ukraine remains alive, but Russia will try to encircle and cut off Kiev in the next several weeks," Murphy added. "The fight for Kiev will be long and bloody and Ukrainians are rapidly preparing for street to street combat."

In this photo provided by the Ukrainian Presidential Press Office, Ukrainian President Volodymyr Zelenskyy delivers his speech addressing the nation in Kyiv, Ukraine, Friday, Feb. 25, 2022. Russian troops bore down on Ukraine's capital Friday, with explosions and gunfire sounding in the city as the invasion of a democratic country fueled fears of wider war in Europe and triggered new international efforts — including direct sanctions on President Vladimir Putin — to make Moscow stop.

In this photo provided by the Ukrainian Presidential Press Office, Ukrainian President Volodymyr Zelenskyy delivers his speech addressing the nation in Kyiv, Ukraine, Friday, Feb. 25, 2022. Russian troops bore down on Ukraine's capital Friday, with explosions and gunfire sounding in the city as the invasion of a democratic country fueled fears of wider war in Europe and triggered new international efforts — including direct sanctions on President Vladimir Putin — to make Moscow stop. ( (Ukrainian Presidential Press Office via AP))

The invasion of Ukraine entered its fifth day on Monday, and strong Ukrainian resistance has prevented Russia from taking the capital city of Kyiv. U.S. and international sanctions have weakened the Russian ruble, harming the invading country's economy. 

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Ukrainian officials had a high-level summit with officials in Belarus Monday to discuss a cease-fire, but the talks ended with no clear progress. Intelligence has suggested that Belarus will send troops to join Russia in the invasion.

Ukraine has put up a valiant defense in the face of overwhelming force – but few experts expect that to dissuade Putin, who has a larger army and more resources available.

President Volodymyr Zelenskyy turned down a U.S. evacuation offer Friday, calling on Western powers to step up their assistance instead.

"The fight is here," he said, according to a translation of his remarks. "I need ammunition, not a ride."

Ukraine

Several buildings in Starobilsk within the Luhansk Oblast region of Ukraine show significant damage because of shelling, according to images shared by the State Emergency Service of Ukraine. (State Emergency Service of Ukraine)