Video has emerged purportedly showing a Russian tank firing on a cyclist in the besieged Ukrainian city of Bucha.

The footage, provided to Ukrainian public broadcasting company Suspilne Media by the Ukrainian military, was reportedly taken on March 3.

The video captures the moment a tank fires at a person riding a bike in the streets of Bucha when the town, northwest of Kyiv, was occupied by Russian forces.

Although the video does not show the moment of death, footage taken by an Associated Press journalist in Bucha earlier this week appears to show a deceased cyclist still lying in the same spot.

-ABC News' Monica Camacho

The International Committee of the Red Cross said Tuesday its team has been released from detention after failing to reach the besieged Ukrainian city of Mariupol.

An ICRC team tasked with escorting evacuation buses to and from Mariupol "was stopped" and "held by police" on Monday in the town of Manhush, about 12 miles west of Mariupol. The team was released Monday night, according to an ICRC spokesperson.

"This is of great relief to us and to their families," the spokesperson told ABC News in a statement Tuesday. "The team is focused now on continuing the humanitarian evacuation operation. This incident yesterday shows how volatile and complex the operation to facilitate safe passage around Mariupol has been for our team, who have been trying to reach the city since Friday."

The ICRC didn't specify which police force had detained its team. However, Ukrainian Deputy Prime Minister Iryna Vereshchuk said in a statement via Telegram on Tuesday that the ICRC team was being held by "the occupation authorities" in Manhush.

Seven humanitarian corridors from the besieged Ukrainian city of Mariupol were opened Tuesday to evacuate some of the 130,000 remaining residents, according to Ukrainian Deputy Prime Minister Iryna Vereshchuk.

Vereshchuk said in a statement via Telegram that the seven evacuation routes will allow Mariupol residents -- many of whom have been living without electricity, food, water or shelter -- to be transported to the city of Zaporizhzhia, about 140 miles northwest of Mariupol.

Mariupol Mayor Vadym Boychenko confirmed on Monday that a convoy of seven buses escorted by the International Committee of the Red Cross could not make it into his southeastern port city to evacuate trapped residents. However, more than 1,500 residents were still able to flee Mariupol using a single humanitarian corridor meant for private cars, according to the mayor.

A brigade of the Russian Ground Forces accused of committing war crimes in the Ukrainian city of Bucha will be sent back to war, according to the Main Directorate of Intelligence of the Ukrainian Ministry of Defense.

"The Russian command will not rotate the personnel in this unit and will throw it back to the front," the directorate said in a statement Tuesday.

As of Monday, Russia's 64th Motor Rifle Brigade was withdrawn from Ukraine to Belarus, according to Ukrainian intelligence. By Wednesday, the personnel will be transported to the western Russian city of Belgorod, just north of the border with Ukraine, with plans to return to the front line in the direction of the northeastern Ukrainian city of Kharkiv, according to Ukrainian intelligence.

"Usually, Russian units leaving the combat zone receive much more time for recovery and rest," the directorate said. "This indicates that 'special tasks' are expected for the 64th Brigade. The first of them: intimidation of inhabitants of settlements of Ukraine. Those who committed the crimes of genocide in Bucha may repeat this again in other cities."

"Another goal of the rapid return of the 64th Brigade to the territory of Ukraine is the rapid 'disposal' of unnecessary witnesses. That is, relocation to a part of the front where they will not have a chance to stay alive to make it impossible to testify in future courts," the directorate added. "The personnel of the unit, aware of the resonance of the events in Bucha and the responsibility for the crimes committed, massively opposes the return to Ukraine. However, the Russian command ignores these sentiments and threatens the tribunal if they refuse to continue fighting. The militaries do not accept reports of dismissal from Russian soldiers."

On Monday, the directorate published online what it said was a list with the names of hundreds of personnel of Russia's 64th Motor Rifle Brigade whom they believe were directly responsible for the atrocities in Bucha. Ukrainian officials have said there is evidence of other Russian units being involved. Russia has denied the claims.

-ABC News' Natalia Kushnir

All Russian troops have left the Ukrainian cities of Kyiv and Chernihiv, withdrawing north toward the borders of Belarus and Russia to consolidate before likely redeploying to the Donbas region in eastern Ukraine, a senior U.S. defense official told reporters Wednesday.

But even with the Russians gone, the territory remains treacherous.

"There are some indications that they left behind mines and things like that, so the Ukrainians are being somewhat careful in some areas north of Kyiv as they begin to clear the ground and clear the territory and re-occupy it," the official said.

While the U.S. hasn't yet seen these troops redeploy elsewhere in Ukraine, it'll likely happen soon, according to the official. Ukrainian forces are preparing for a major fight in Donbas, the official said.

The official also said the Pentagon is "monitoring" an apparent nitric acid explosion in Ukraine's Luhansk region, which Russia blamed on Ukraine.

"We've seen the Russians claim that this was a Ukrainian attack on this. We do not believe that is true," the official said. "We do believe that the Russians are responsible, but exactly what they used when they did it, why they did it, what the damage is, we just don't have that level of detail," the official said.

The official also noted that a small number of Ukrainians currently in the U.S. for "professional military education" were pulled aside for a couple days of training on Switchblade drones, which the U.S. is sending overseas as part of its military aid, according to the official.

"Although it's not a very difficult system to operate, we took advantage of having them in the country to give them some rudimentary training on that," the official said.

-ABC News' Matt Seyler