Russia said on Thursday that Switzerland has lost its neutral status and cannot represent Ukraine diplomatically in Russia, blaming Bern's decision to impose sanctions on Moscow.

Switzerland said on Wednesday that Ukraine had asked Bern to represent it in Russia.

"Unfortunately, Switzerland has lost the status of a neutral state and cannot act either as a mediator or as a representative of interests," Russian foreign ministry spokesman Ivan Nechayev told reporters.

He confirmed that Bern had asked Russia if it would agree to Switzerland representing the interests of Ukraine in Russia and vice versa.

Nechayev stressed that Switzerland had been supporting the Kyiv government and slapped sanctions on Russia.

"It is completely incomprehensible how one can offer mediation, representation or other goodwill services with such behaviour," he added.

Ever since Russian President Vladimir Putin sent troops to Ukraine on February 24, Switzerland -- renowned for its neutrality -- has said it stood ready to provide diplomatic assistance and to serve as a go-between.

Moscow has been angered by Bern's decision to follow the neighbouring European Union in imposing sanctions on Russia.

Switzerland has a long tradition of acting as a protecting power, first playing the role during the Franco-Prussian War in 1870-71.

The wealthy Alpine country, which has held such mandates hundreds of times since then, currently represents the diplomatic interests of a range of countries including Russian interests in Georgia and vice versa. b