The presidential campaign got launched amid a period of intense diplomacy for Mr. Putin.
On Wednesday, he made quick trips to the United Arab Emirates and Saudi Arabia. On Thursday, he spoke to international investors, many of them from China and India, at a conference in Moscow. Later Thursday, he was scheduled to meet with President Ebrahim Raisi of Iran.
Many parties and potential candidates have featured in previous elections, but this time, following the invasion of Ukraine, the political landscape is vastly different.
Numerous outspoken critics of Mr. Putin and his policies have had to flee Russia. Aleksei A. Navalny, whose presidential bid was rejected by the Central Electoral Commission, is serving a lengthy prison term in a penal colony. On Thursday, Mr. Navalny’s political allies called on Russians to vote for any candidate other than Mr. Putin.
“Putin has been terrorizing our country for 24 years,” said Ivan Y. Zhdanov, the director of Mr. Navalny’s anti-corruption foundation, in a video announcing the effort. “He plans to do it indefinitely.”
So far, three Russian politicians have announced their intention to run against Mr. Putin.
Boris B. Nadezhdin, a municipal deputy in a suburban town near Moscow, has said the end of the war was his top priority. Igor Girkin, a nationalist warlord and blogger currently in jail awaiting trial on extremism charges, has argued for a tougher approach in Ukraine. Yekaterina S. Duntsova, who also campaigns against the war, has garnered limited national appeal so far.
In order to register as candidates, they must collect thousands of signatures from supporters, a requirement that can be a tough bar to overcome for opposition politicians in a country where opposition activity has been sharply curtailed by the state.