Russian forces are continuing their offensive on the eastern Ukrainian stronghold of Bakhmut. Britain's defense ministry says the city is becoming increasingly isolated.

A pro-Russian leader in the eastern region of Donetsk, Denis Pushilin, said on social media on Saturday that Russian forces are closing in on the stronghold.

The British defense ministry's intelligence update on Sunday said Russia has continued to make small advances in its attempt to encircle Bakhmut.

The ministry added that the two main roads into the city are likely now both threatened by direct fire, following the advances.

It also said, "Earlier in the week, Wagner paramilitary forces highly likely seized a subordinate route which links Bakhmut to the town of Siversk."

Ukrainian President Volodymyr Zelenskyy said in a video speech on Saturday that the situation at the front was "getting tougher."

He said that "the occupier throws in more and more of its forces to break our defenses."

On Friday, Zelenskyy stressed at a news conference that Ukraine would fight to hold on to Bakhmut for as long as it could.

He said that if supplies of long-range weapons are quickened, Ukraine not only will not leave the stronghold, but will also "begin to deoccupy Donbas, which has been occupied since 2014."

Ukraine is calling for the provision of long-range rockets, missiles and other weapons from Western nations in an apparent bid to step up its counteroffensive.