Vladimir Putin said on Saturday he would name a preferred successor to follow him as Russian president and vowed to ensure a smooth handover of power when he steps down in 2008.

Putin, who was himself made acting head of state by then-President Boris Yeltsin to ensure his election, has long rejected suggestions he should change the constitution and stand for a third term.

The identity of his successor has become the country's hottest political topic. He gave no clues as to whom he would support on Saturday, saying that was a question for the people, but made clear he expected a role in the choice.

"I think I would be right to express my point of view on one candidacy or another, and I will do this," Putin told reporters in the Black Sea town of Sochi, agencies reported.

"I have certain ideas about how to set up the situation in the country in this period of time so as not to destabilise it, so as not to scare the people and business."

On Friday, his government launched a mass purge of the customs and security services in an anti-corruption drive. He pledged on Saturday that the 10 high-profile sackings were just the start of the assault.

State television on Saturday led on his campaign against corruption, which has seen the arrests and sackings of dozens of top officials.

"The work is not finished, and not just in the customs department," he said, in reference to the purge.

"In our country, corruption is unacceptably high."

Defence Minister Sergei Ivanov and First Deputy Prime Minister Dmitry Medvedev are widely seen as frontrunners to be picked by the Kremlin to follow Putin.

The lawyer Medvedev and ex-spy Ivanov come from different backgrounds, but are both seen as likely to maintain Putin's course of ensuring a strong Kremlin, and being assertive abroad.

"Everyone is concerned about stability and are wondering what will happen after 2008," Putin said.

"I cannot just say 'I've done my job' and you sort the rest out yourselves. To the last minute of my holding the presidency, I will responsibly do my duty," Putin was quoted as saying.

Putin said that he could not tell the Russian people who to vote for.

"The final choice will come down to the Russian citizen. You can't impose someone. The reaction could be opposite to the one intended," he said.