MOSCOW—Russian President Vladimir Putin said he doesn’t aim to hold his post for life but doesn’t rule out seeking another term in 2018, a move that could make him the country’s longest-serving leader since Joseph Stalin.

In an interview with state-controlled TASS news agency, the 62-year-old Mr. Putin said that for him to remain “in the president’s chair forever” is “not good, and (is) detrimental for the country, and I do not need it as well.”

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