Deputy mayor Serhiy Orlov told the BBC that “battles for Mariupol continue”.

He also denied reports about a marine brigade which posted to Facebook about running out of ammunition and facing a “last battle”.

“The information about the marines is fake. I don’t comment on fakes.”

“The Russians temporarily occupied part of the city. Ukrainian soldiers continue defending the central and southern parts of the city, as well as industrial areas and so on,” Mr Orlov said.

In a Facebook post, Ukrainian armed forces Commander-in-Chief Valerii Zaluzhnyi said the military still had stable, open lines of communication with its soldiers inside the city.

Mariupol lies between the pro-Russia breakaway regions of Donetsk and Luhansk in the east, and annexed Crimea in the south. Seizing the city has been a major goal of the Russian offensive.

In briefings, officials say Russia is re-equipping its combat units and adding fresh troops – which will take time. In the meantime, Western economic and military aid for Ukraine could prove valuable in preparing for any renewed offensive.

Meanwhile, Ukraine’s President Volodymyr Zelensky said that tens of thousands of people had likely been killed in Mariupol.

The BBC has not verified the figure, but reports from the region and the refugees fleeing the city spoke of bodies lying in the streets and most buildings damaged or destroyed.

The 36th marine brigade earlier posted on Facebook warning that after 47 days of defending the city, the unit had been surrounded by the Russian army, and was facing “hand-to-hand combat”.

The post – which Mr Orlov labelled a fake – promised Ukrainians its soldiers “did everything possible and impossible” to stop the Russian advance.

“Today will probably be the last battle, as the ammunition is running out… it’s death for some of us and captivity for the rest,” it said.

It also complained about a lack of support from other parts of the Ukrainian military, with aid promised which never came.

The post said the marines have been pushed back to the Azovmash factory in the city. It is believed there is also fighting inside the Azovstal industrial zone, which is on the coast.

Some experts expressed scepticism about the post, suggesting that the Facebook page could have been hacked by Russian operatives. But others are sure that it is authentic.

Mariupol has seen little let-up in the fighting since the war began, with little humanitarian aid, long delays to evacuations, and reports of civilians starving or being forcibly removed to Russia-held territory.

The head of pro-Russia Donetsk separatists, Denis Pushilin, told Russian media that he thought more than 5,000 people may have been killed, though he blamed Ukrainian forces.

Russian forces have continued to slowly advance and seize more of the city in recent weeks – unlike in the rest of Ukraine, where they have “refocused” military action around the breakaway regions in the east, largely pulling out of other areas such as near the capital, Kyiv.

As a result, Ukrainian officials are focusing on evacuating civilians from eastern towns and cities in anticipation of a renewed assault in some places.

Nine new humanitarian corridors have been agreed between Ukraine and Russia, to allow civilians to flee, including from Mariupol.

Ukraine is also putting on extra trains to extract people from the Donetsk and Luhansk regions, where Russia is focusing its efforts.

Mr Zelensky said that tens of thousands of pro-Russian troops are believed to have redeployed and massed in the area, and a renewed offensive is widely expected to come soon.