MOSCOW (Reuters) -- Russia's upper house of parliament has given its assent to constitutional amendments extending the presidential term from four to six years.
Critics of the Kremlin say the change could be part of a plan for ex-President Vladimir Putin, now prime minister, to return to his old job, although officials deny this.
The legislation has been rushed through the parliamentary process in less than four weeks with little dissent, except from opposition Communists who do not have enough votes to block it.
The law was nodded through the Federation Council with 144 votes in favor and one against. The council comprises senators representing Russia's regions.
The amendments have now been passed by both chambers. The State Duma, the lower house, approved the amendments on final reading on November 21.
They now only need to be ratified by two-thirds of regional parliaments -- which are almost all dominated by Kremlin loyalists -- before they can take effect.
Police detained a lone anti-Kremlin protester outside the Federation Council building after he tried to unfurl a banner criticizing the plans, a Reuters reporter said.
The proposal was first raised by President Dmitry Medvedev in his state-of-the-nation address on November 5.
The longer Kremlin term will not apply to Medvedev's present mandate, and Putin's spokesman has said there is no plan for him to make a comeback in an early presidential election.