After months of bombardment, Ukraine's military announced on Tuesday that it was trying to withdraw all remaining troops from their last foothold in the beleaguered port of Mariupol, relinquishing control of the city to Russia.

The evacuation of hundreds of combatants, many of whom were injured, to Russian-held areas certainly signified the conclusion of the longest and bloodiest fighting of the Ukraine war and a huge loss for Ukraine.

According to Ukraine, tens of thousands of people perished in the city of Mariupol as a result of a Russian siege.

Hundreds of Ukrainian soldiers and residents hid behind the city's Azovstal steelworks when the remainder of Mariupol fell solidly into Russian hands.

The plant's civilians were evacuated in recent weeks, and more than 260 servicemen, some of whom were wounded, fled for Russian-controlled territory late Monday night.

"The 'Mariupol' garrison has completed its combat duty," said a statement from the General Staff of the Ukrainian Armed Forces.

"The high military leadership directed commanders of units stationed at Azovstal to spare the lives of personnel... Defenders of Mariupol are the heroes of our time," the statement continued.

Ukrainian Deputy Defense Minister Anna Malyar stated that 53 injured troops from the steelworks were taken to a hospital in the Russian-controlled town of Novoazovsk, approximately 32 kilometers (20 miles) to the east, while another 211 people were taken to the Russian-backed separatist-controlled town of Olenivka.

She said that all evacuees could be subject to a prisoner swap with Russia.

About 600 troops were estimated to have been inside the steel facility. The Ukrainian military has indicated that efforts are being made to evacuate anyone still inside.

Ukrainian President Volodymyr Zelenskiy stated in an early-morning address, "We hope that we will be able to rescue the lives of our men.  There are critically injured individuals amongst them. They are being cared for."

Monday night, Reuters spotted five buses transporting troops from Azovstal arrive in Novoazovsk. In one, marked with a Z like many Russian military vehicles in Ukraine, three levels of stretchers contained men. A man was rolled out with his head wrapped in thick bandages.

Moscow describes its nearly three-month-old invasion of Ukraine as a "special military operation" to clear the country of Nazis, a claim Kyiv and its Western allies deem to be a justification for an unprovoked attack.

Russia's invading forces have apparently suffered defeats, as troops were expelled from the north and surrounding areas of Kiev in late March.