The US think tank Institute for the Study of War says Ukrainian forces launched a counterattack on Tuesday in the eastern province of Kharkiv that likely drove back Russian forces.
It added that Russia's deployment of forces from Kharkiv and eastern Ukraine to Ukraine's south is likely enabling Ukrainian counterattacks of opportunity.
The British Defence Ministry said on Wednesday that Russia's planned main effort is probably an advance on Bakhmut in the eastern region of Donbas.
But it pointed out that Russian commanders face a dilemma of whether to deploy operational reserves to support this offensive, or to defend against continued Ukrainian advances in the south.
The General Staff of the Armed Forces of Ukraine announced on Wednesday that about 40 Russian military strongholds had been attacked.
The International Atomic Energy Agency on Tuesday called for a security zone to be established around the Zaporizhzhia nuclear power plant, which is under the control of Russian forces.
Russian Foreign Minister Sergey Lavrov said on Wednesday that Russia has requested additional explanations from the IAEA because there are a number of issues that need to be clarified.
In a speech at an international economic forum, Russian President Vladimir Putin criticized Ukrainian forces for attacking Zaporizhzhia and claimed that Russia has no military equipment at the plant.