(Reuters) - Ramzan Kadyrov, head of Russia's Chechnya region and close ally of President Vladimir Putin, proposed on Saturday that a presidential election due next March should either be postponed due to the war in Ukraine or limited to one candidate - Putin.

The Kremlin leader, who turned 71 on Saturday, has said he will not announce if he will run before parliament calls the election, which by law it is due to do in December.

Putin has dominated Russia for more than two decades and, having suppressed all significant political opposition, would be all but certain to win an election and, as widely expected, extend his stay in the Kremlin to 2030.

However, Russia's failures in the war, which Moscow calls a "special military operation", have made events less predictable.

The state-run RIA news agency said Kadyrov had spoken on Saturday at a rally in the centre of the Chechen capital Grozny, put at 25,000 people, to mark Putin's birthday.

"I propose now, while the 'special military operation' is under way, to unanimously decide that we will have one candidate in the elections - Vladimir Vladimirovich Putin," Kadyrov was quoted as saying.

"Or temporarily call off the elections, because there's no one else who could defend our country today," added the Chechen strongman, a Putin protege who has raised his public profile since the war began.

Putin's full-scale invasion of Ukraine in February 2022 has become his biggest challenge.

Far from swiftly taking control of Russia's neighbour and thwarting its attempts to draw closer to the West, he controls less than a fifth of Ukraine, with front lines static, military spending soaring, and hundreds of thousands of Russians fighting a war they did not volunteer for.

He has also ruptured relations with the West, which has imposed sweeping economic sanctions, armed Ukraine at huge cost, and expanded and reinforced the U.S.-led NATO alliance.

(Reporting by Reuters; Writing by Kevin Liffey; Editing by Ros Russell)