Ukrainian President Volodymyr Zelenskyy has denied Russia's claim that its forces were taking full control of the battleground city of Bakhmut.

Zelenskyy spoke at a news conference in the western Japanese city of Hiroshima on Sunday evening after he attended the Group of Seven summit earlier in the day.

He said Russian forces have not captured Bakhmut in the eastern Ukrainian region of Donetsk. He added that Ukrainian soldiers are performing a very important task in the city although he did not state exactly where they are operating.

Ukraine's army commander Colonel General Oleksandr Syrskyi posted a video on his social media channel on Sunday that shows him visiting soldiers on the frontline near Bakhmut. He stressed that Ukrainian forces continue their offensive on the flanks near Bakhmut.

The Russian presidential office said on Sunday morning that President Vladimir Putin had congratulated the private military firm Wagner Group and Russian service personnel on the completion of the operation to "liberate" the city.

The announcement followed claims by the Russian defense ministry and Wagner leader Yevgeny Prigozhin that their forces had fully captured Bakhmut.

Prigozhin also announced on Saturday that Wagner forces would pull out of the city on Thursday or later.