Since Russian troops started their encirclement of Mariupol in early March, up to 180,000 people are waiting to be evacuated from and around the besieged Ukrainian port city of Mariupol, with a total of 150,000 people already evacuated so far, Mayor Vadym Boychenko said on Wednesday.

There are growing signs Russia could be on the brink of capturing Mariupol while Ukrainian troops have said they are running out of ammunition.

1,000 Ukraine marines surrender in Mariupol, says Russia

Russia's defense ministry said on Wednesday that 1,026 soldiers of Ukraine's 36th Marine Brigade, including 162 officers, had surrendered in Mariupol.

Mariupol, which has been encircled by Russian troops for weeks, has seen the fiercest fighting and the most comprehensive destruction since Russia launched its operation in Ukraine on February 24.

Surrounded and bombarded by Russian troops for weeks and the focus of some of the fiercest fighting, Mariupol would be the first major city to fall and the captured would help secure a land passage between the eastern areas and Crimea.

"In the town of Mariupol, near the Ilyich Iron and Steel Works, as a result of successful offensives by Russian armed forces and Donetsk People's Republic militia units, 1,026 Ukrainian soldiers of the 36th Marine Brigade voluntarily laid down arms and surrendered," the ministry said in a statement.

Ukraine's general staff said Russian forces were proceeding with attacks on Azovstal and the port, but a defense ministry spokesman said he had no information about any surrender.

On Monday, the 36th Marine Brigade said it was preparing for a final battle in Mariupol that would end in death or capture as its troops had run out of ammunition.

Ukrainian President Volodymyr Zelenskiy said thousands of people are believed to have been killed in Mariupol and Russia has been massing thousands of troops in the area for a new assault. 

Russia: U.S., NATO weapon transports in Ukraine are legitimate targets

Attempts by the U.S. and other Western countries to slow Russia's special operation in Ukraine will be curbed, Russian Deputy Foreign Minister Sergey Ryabkov said in an interview with TASS on Wednesday. 

"We are also making it clear to the Americans and other Westerners that attempts to slow our special operation and inflict the most possible damage to Russian units and the units of the Donetsk People's Republic (DPR) and the Luhansk People's Republic (LPR) will be curbed in a tough manner," he said.

Ryabkov also said Russia will regard U.S. and NATO vehicles that transport weapons in Ukraine as legitimate military targets. 

(With input from agencies)