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

Russian troops have advanced about 3 miles toward Kyiv in the past day, bringing them within roughly 9 miles of the city center, according to a senior U.S. defense official.

The troops are to the northwest of Kyiv, in the area of the Hostomel Airport, which is about 5 miles from the outer city limits.

Two lines of advance from the northeast are also making progress on their push to Kyiv. The closest of these troops is now approximately 25 miles from the heart of the city, the official told reporters during a Thursday evening briefing.

Some troops from one of those lines of advance, emanating from above the town of Sumy, seem to have turned around, heading back northeast, though the reason for the about-face is unclear, the official said.

Kyiv remains "well-defended" by Ukrainian forces, the official said. Security assistance continues to flow into Ukraine, including air-defense systems, according to the official.

Since the start of the invasion, Russian forces have fired more than 775 missiles against Ukraine, the official said.

-ABC News' Matt Seyler

Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, spoke with his military counterparts in France, Poland, Romania and Bulgaria Thursday about the latest developments in Ukraine, according to the Pentagon.

While the Pentagon didn't provide many details about his discussions with the military leaders, it said they shared assessments and intelligence.

Milley also discussed the recent deployment of U.S. military forces to Poland and Romania with their respective military leaders, according to the Pentagon.

-ABC News' Luis Martinez

While tens of thousands of Ukrainians were able to flee the country via humanitarian corridors on Thursday, those still in Mariupol have not been able to leave, as the city is under total siege by Russian forces.

A second attempt for residents to leave on Thursday was abandoned as the Russian military continued to bombard the Mariupol and the humanitarian passages surrounding it, Ukrainian President Volodymyr Zelenskyy said during a press briefing Thursday.

About 300,000 are suffering from lack of water, power and food, said Iryna Vereshchuk, a vice prime minister helping oversee the evacuations. Russia also destroyed and mined surrounding cities, Vereshchuk said.

Albert Khomyak, who lived in Mariupol's eastern outskirts, told ABC News that Russian troops have now entered their street.

"They are trying to destroy Mariupol, that way to destroy the resistance," he said.

Khomyak was somehow able to drive with his family in their own car out of the city, he said.

About 16,000 people are estimated to have evacuated Ukraine on Thursday now that the corridors near the northern Sumy region and some of the towns just northwest of Kyiv have been firmed up, Russian officials said.

But the ceasefires that allow these evacuations are temporary and very imperfect, and sporadic firing still happens throughout them.

The ceasefires then end at 9 p.m., when full-scale offensive attacks from Russia begin again.

-ABC News' Fidel Pavlenko and Natalie Vikhrov

The soaring gas prices Americans are experiencing are a result of the "stand" being taken for democracy in Ukraine, Rep. Raul Ruiz, D-Calif., said in a press conference Thursday from Philadelphia, where a retreat for House Democrats is ongoing.

Ruiz recast rising gas prices in a different light, saying they are part of the fight for democracy and in support of Ukraine against Russia.

"We have to ask ourselves, what is it we stand for as a democracy?" Ruiz, the chair of the Congressional Hispanic Caucus, said. "To protect other democracies, and to protect us from autocracies and to show solidarity? What is the price that we as individuals will want to contribute in solidarity with the Ukrainian people?"

Ruiz said his family are among the millions of Americans feeling the effects of the record-high prices.

"I, for one, am going to pay that price," Ruiz said. "If it means paying a few extra cents at the gas tank, then we're willing to pay that."

-ABC News' Ben Siegel