General Konstantin Pulikovsky said he was using helicopters to shower the shattered city with leaflets warning civilians to leave within 48 hours, after which he would begin military operations against the separatists "using all available means", according to the news agency Interfax. Although he said his decision was in response to continuing Chechen attacks on his forces - despite a ceasefire - it came after a day of mounting evidence that before they strike any lasting agreement the Russians intend to try to regain control of Grozny, most of which they lost to a rebel assault a fortnight ago.
As the estimated 2,500-3,000 Chechen fighters are well armed and dug in, and are unlikely to leave without a fight. A long conflict is now looming which would bring widespread loss of life and suffering.
Last night, there was a flurry of reports in Moscow that the Russian assault had already begun, after a rebel spokesman reported that federal troops were attacking several areas of the city. Although the Russian authorities denied any such operation, there were reports of intermittent fighting, destroying the brief lull that followed Saturday's ceasefire agreement.
General Pulikovsky's ultimatum points to a deepening rift between the hardline generals and other top officials - who are determined to try to crush the separatists - and Alexander Lebed, the secretary of the Security Council and presidential envoy to Chechnya.
It was not clear whether Mr Lebed was informed, or approved, of yesterday's announcement. In recent days, he has struck a sympathetic note in his handling of the Chechens, earning him the respect of rebel leaders and igniting a flicker of hope that a truce would be agreed.
Earlier Mr Yeltsin, in comments released by his press secretary, appeared to ignore Mr Lebed's more conciliatory stance by ordering him to restore the situation in the republic's capital to "the law and order of 5 August" - the day before Grozny was stormed. There were doubts, however, over whether the latest move was Mr Yeltsin's own initiative, or that of his inner circle, who include opponents of Mr Lebed.Reuse content