There has been widespread speculation that Putin will nominate his successor or amend the Constitution to stay in power, but the president has repeatedly denied both options as undemocratic.
Speaking at an annual Kremlin live televised news conference with Russian and foreign journalists, Putin said: "I have said on many occasions that there will be no successor. There will be candidates for president of Russia."
But Putin said he reserved the right to express his opinion regarding candidates during the campaign.
"I am also a citizen of the Russian Federation, which I am very proud of, and I certainly reserve the right to express my preferences. But I will only do so during the campaign," he said.
Several figures have been frequently mentioned as Putin's proteges for the post, including First Deputy Prime Minister Dmitry Medvedev and Defense Minister and Deputy Prime Minister Sergei Ivanov.
Medvedev, who Putin put in charge of sensitive welfare "national" projects, has received much coverage on television recently. And Ivanov, with a KGB background like Putin, has been active on the international scene.
Putin is extremely popular in Russia and is credited by many for ensuring relative order and growth in the country. But he has been increasingly criticized in the West for totalitarian tendencies, including a crackdown on the free media and the political opposition, and the use of energy resources to advance political goals.
