G7 foreign ministers have said they will pursue further sanctions against Russia, following President Vladimir Putin's move to mobilise reservists for the offensive in Ukraine.

Ministers from the Group of Seven "deplored deliberate Russian escalatory steps, including the partial mobilisation of reservists and irresponsible nuclear rhetoric," they said in a statement on Wednesday night.

The G7 would "pursue further targeted sanctions and are committed to sustained economic and political pressure on Russia," they said after a meeting on the fringes of the United Nations General Assembly.

"We will study, we will adopt, new restrictive measures, both personal and sectoral," EU foreign policy chief Josep Borrell, who attended the meeting, told reporters earlier on Wednesday after a meeting with his European colleagues.

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'Sham referenda'

The G7 ministers from Canada, the United States, France, Germany, Italy, Japan and the United Kingdom, as well as the European Union's top diplomat, also condemned a plan to hold "sham referenda on sovereign Ukrainian territory" in Donbass.

The voting "cannot be free or fair" while Russian forces are present, they added.

The ministers repeated a pledge made at the beginning of September to "finalise preparations" for the implementation of a price cap on Russian oil.

They also called on Russia to "hand back the control" to Ukraine of the Zaporizhzhia nuclear power plant, which has been the target of strikes in recent weeks.

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