Speaking to Al Jazeera, a soldier based in Donetsk said: “We are firing one shell in response to 10 ones from their side.”

Nikolay Mitrokhin of Germany’s University of Bremen also told the same outlet: “In the Donetsk front, there is a large hole through which Russians can advance in three, four directions.

“The situation is pretty bad, but it’s not clear what reserves Ukrainian forces will find and how Russian forces can break through minefields under constant drone attacks,” he said.

Mikhail Zhyrokhov, a Ukraine-based military analyst, told Radio NV: “This is a breakthrough not of tactical but of strategic level. And that’s why Russians will only strengthen their pressure.

“The situation around Ocheretyne is very difficult and tends to only get worse. Because such an advance gives Russians huge advantages on the flanks. That’s why holding other towns, another line of defence will be very hard.”

Ukraine is still waiting for the $60billion (£49billion) of military aid to make its way to the country after it was finally approved by lawmakers in Washington.

On Tuesday, Ukrainian President Volodymyr Zelensky said: “Timely support for our army. Today I don’t see anything positive on this point yet. There are supplies, they have slightly begun, this process needs to be sped up.

“The Russian army is now trying to take advantage of a situation when we are waiting for supplies from our partners… and that is exactly why the speed of deliveries means stabilising the front.”