The head of a district in Russia's southern republic of Dagestan has been killed in Moscow, officials say.
Alimsultan Alkhamatov was shot dead on Sunday evening as he was getting out of his car, prosecutors said. His driver was badly wounded.
A man has been arrested in connection with the attack, the latest against a North Caucasus official.
Dozens of militants and members of the security forces have been killed in the region in the last few months.
Earlier on Sunday, two senior police officers were shot dead in an attack in Dagestan.
"There is a real hunt on for high-ranking officials in Dagestan," a security source was quoted as saying by Interfax news agency.
The influential head of a region east of Dagestan's capital Makhachkala, Mr Alkhamatov had reportedly been the target of three previous assassination attempts, the agency added.
In June the republic's interior minister was shot dead.
Two weeks later, the president of nearby Ingushetia, Yunus-Bek Yevkurov, was critically injured by a car bomb in an apparent assassination attempt.
Russian forces have fought two wars against separatists in the mainly Muslim republic of Chechnya since 1994. The conflicts claimed more than 100,000 lives and left it in ruins.
Chechnya has in recent years been more peaceful, but the fighting has spread to Dagestan and Ingushetia, where correspondents say a violent Islamist insurgency is growing.