A Russian politician on hunger-strike to protest alleged fraud in a recent mayoral race says he may take up an offer to travel to Moscow to review evidence of vote-rigging, but only if doctors rule him fit enough.

Oleg Shein, who ran for mayor in the southern city of Astrakhan on March 4, was quoted by Russian news agencies Sunday as saying he could take up the offer from the Central Election Commission chief Vladimir Churov to watch videos allegedly containing evidence of fraud.

Churov made the offer Thursday, on the condition Shein suspend his hunger strike. Shein wouldn’t say Sunday whether he was ready to end his strike.

Shein — who appears very frail in videos on his blog — has refused food for a month in protest at what he calls rampant fraud in favor of a Kremlin-backed candidate that denied him rightful victory. He said on his blog Sunday that doctors had given him a glucose injection to compensate for his loss of body sugar.

Officials have said violations in the mayoral vote were not widespread and could not have influenced the outcome.

In an expression of support, thousands of protesters took to Astrakhan’s streets over the weekend. Shouting slogans such as “Astrakhan will be free,’’ the protesters for about four hours marched through the city, stopping at a park, a square and Shein’s headquarters, under the eye of phalanxes of police. At least three arrests were reported.

Shein’s struggle has become a rallying call for Russia’s opposition forces struggling to maintain momentum in the face of Vladimir Putin’s victory in last month’s presidential election.

Putin, who oversaw a steady rollback in democratic freedoms during two terms as president and then as prime minister, won a new six-year term in March’s vote and has shown disdain for protesters’ demands for changes.