Western analysts say Russia's offensive in the eastern Ukrainian region of Donetsk may be losing steam as Ukrainian troops continue all-out resistance.

Russian private military firm Wagner Group and Ukrainian forces are locked in a fierce battle for full control of the Ukrainian stronghold of Bakhmut.

A US think tank, the Institute for the Study of War, said on Wednesday that personnel losses and ammunition shortages are making it difficult for Russian forces to take control of central Bakhmut.

The think tank cited Ukrainian military sources as saying that Russia's offensive has significantly decreased on the eastern frontline of Bakhmut.

The institute said, "The overall pace of Russian operations in Ukraine appears to have decreased compared to previous weeks."

The British defense ministry said on Thursday that Russian attempts to assault Vuhledar, another battleground in the Donetsk region, "have almost certainly slowed" over the past week.

The ministry added, "This follows repeated, extremely costly failed attacks over the previous three months."

Russian presidential spokesperson Dmitry Peskov spoke to reporters on Thursday about the ninth anniversary of Moscow's annexation of Crimea in southern Ukraine on March 18.

He said relevant meetings will be held online on Friday and Saturday.

Last year, President Vladimir Putin spoke at an event on that occasion and justified what he calls the "special military operation" in Ukraine.

Russian newspaper Vedomosti said on Thursday that a similar large-scale event is unlikely to take place. It reported an expert's view that it is not appropriate to be overjoyed in view of the mobilization and other factors.