Russia-Ukraine updates: Putin says 'certain positive movements' in negotiations

Russia claimed Wednesday to have captured Ukraine's southern port city of Kherson, the largest Ukrainian city to fall to Russian forces since the start of the invasion.

"Russian forces have taken full control of the Kherson regional center," Russian Ministry of Defense spokesman Igor Konashenkov said at a press briefing Wednesday.

Russia-backed separatist forces in eastern Ukraine have also seized several cities and towns, advancing nearly 100 miles since launching the offensive, according to Konashenkov.

"Ukrainian servicemen will go home as soon as they make a written pledge not to take part in the hostilities," he said.

Meanwhile, Russian forces have "disabled" the instrument room of the the main television tower in Ukraine's capital, Kyiv, "putting an end to information attacks on Russia," according to Konashenkov, who noted that "no damage was done to residential buildings in the course of the strike."

Konashenkov also claimed that Russian aircraft had delivered a "massive strike" on Ukraine's military infrastructure on Wednesday.

"Sixty-seven sites have been hit," he added. "In all, 1,502 elements of Ukrainian military infrastructure have been disabled in the course of the operation. These include 51 command and communications centers belonging to the Ukrainian Armed Forces, 38 S-300, Buk M-1 and Osa air defense missile systems and 51 radar stations."

-ABC News' Anastasia Bagaeva

The Boeing Company has suspended all parts, maintenance and technical support for Russian airlines as the conflict continues, the company announced Tuesday.

This is expected to have a significant impact on Russian carriers, as planes need constant maintenance.

"We have suspended major operations in Moscow and temporarily closed our office in Kyiv," Boeing said in a statement. "We are also suspending parts, maintenance and technical support services for Russian airlines. As the conflict continues, our teams are focused on ensuring the safety of our teammates in the region."

-ABC News' Sam Sweeney

Iowa Gov. Kim Reynolds implied Russia's attack on Ukraine is connected to a lack of leadership from President Joe Biden in the Republican response to the State of the Union address, saying Biden has "sent us back in time" to the 1970s and '80s, when the "Soviet army was trying to redraw the world map."

Reynolds said Biden has failed on his promise to make America respected around the world once more and criticized Biden for the lead-up to the invasion, including waving sanctions against Russia and "focusing on political correctness."

"Weakness on the world stage has a cost," Reynolds said. "... We can’t project strength abroad if we’re weak home."

In his first State of the Union address, President Joe Biden began by discussing the war in Eastern Europe and condemning Russian President Vladimir Putin’s invasion of Ukraine.

Biden invoked the strength of the Ukrainian people amid the attack, lauding the civilians who took up arms to defend their country and highlighting the work Ukrainian Ambassador to the U.S. Oksana Markarova has done on behalf of her people.

"She’s bright. She’s strong, and she’s resolved," Biden said as first lady Jill Biden hugged Markarova.

Many lawmakers in attendance showed their support for Ukraine by wearing color-coordinated outfits and lapel pins in blue and yellow.

Biden described the invasion as "premeditated and totally unprovoked," vowing, alongside NATO allies, to hold Putin accountable with sanctions on the Russian economy and Putin and the oligarchs themselves.

"When dictators do not pay a price for their aggressions, they cause more chaos," Biden said. “They keep moving.”

Biden announced that American airspace would be closed to all Russian flights and pledged $1 billion in direct assistance to help "ease suffering" in Ukraine.

The president also "made clear" that while American forces would not go fight in Ukraine, he has mobilized the military to protect NATO countries.

"The United States and our Allies will defend every inch of territory that is NATO territory with the full force of our collective power," he said.

-ABC News' Julia Jacobo and Ben Gittleson