Moscow has been abuzz for months with speculation about whether Mr. Putin, who has been in power for 20 years, will step down at the end of his current and supposedly final term in 2024.

Wary of declaring himself a lame duck and triggering a destabilizing succession struggle, Mr. Putin has kept his plans secret. His comments on Thursday were so ambiguous that they set off another round of Kremlin tea-leaf reading.

His musing publicly about revising the Constitution, which bars a president from serving more than two successive terms, raised the possibility that he may want to run for a third consecutive term — which would keep him in office through 2030 — and possibly more.

But it could also mean that he wants to remove only the reference to consecutive terms, which would actually strengthen the two-term limit. That would prevent future presidents from repeating his own controversial maneuver in 2008, when he stepped down after two terms to become prime minister — while holding onto most of his power — only to return four years later for a third presidential term. He also found another way to extend his grip on power, lengthening the terms from four years to six.

In an interview with state television after the news conference, Mr. Putin played down the significance of his comment, saying that he had simply answered a question put to him about the Constitution, adding, “I can’t say this was something prepared from my side.” He said he was open to the idea of increasing the powers of Russia’s Parliament, which has become little more than a rubber stamp and cheerleading squad for the Kremlin.