Galina Starovoitova, a parliamentary deputy for the reformist Democratic Russia party, had announced her intention of contesting Russia's next presidential election in the year 2000.

An aide who was with her, Ruslan Linkov, was seriously injured.

The police have not released any other details.

The Russian news agency, Tass, reported that Mr Yeltsin has ordered Russian Interior Minister Sergei Stepashin, Federal Security Service Head Vladimir Putin and Russian Prosecutor General Yuri Skuratov to investigate the murder.

Mrs Starovoitova, 52, came from Chelyabinsk in the Urals, and had advised President Yeltsin on ethnic issues and human rights.