GROZNY, Russia (AP) -- A deadline set by Russian forces expired early today in the Chechen capital, where Boris Yeltsin's security chief said he had averted a major assault threatened by the Russian military.
Putting his new Kremlin authority on the line, Alexander Lebed flew to Chechnya and said after meeting with both sides that he was personally withdrawing the army ultimatum.
There was no immediate word from Russian commanders, however, and it remained unclear whether Lebed's efforts -- and reports that the Chechens had agreed to a new informal truce -- would prevent the attack or rule out a new offensive.
The Russian military had given civilians until 8 a.m. today to leave Grozny or face a devastating aerial and ground attack, prompting tens of thousands of people to flee by foot or by car in the last few days.
Anywhere from 50,000 to 200,000 civilians remained in the destroyed city, which had a prewar population of 400,000.
Lebed, shuttling between the two military camps into the night Wednesday, dismissed the army's ultimatum, saying no such assault would occur today.
But the Russian military, which unleashed a savage artillery assault on the city Wednesday, is riddled with dissension and infighting and has ignored past orders by Yeltsin not to bomb Grozny. It issued no reply to Lebed's assurances.
Past cease-fire deals have failed, and the ailing Yeltsin has been mum on the 20-month-old war for weeks.
''No such bombardments will happen,'' the ITAR-Tass news agency quoted Lebed as saying after talking with rebel chief Zelimkhan Yandarbiyev and Russian military commander Aslan Maskhadov.
''It's already clear to everyone, to my mind, that issuing an ultimatum was a bad joke,'' Lebed said.
Lebed said the rebels had agreed to an immediate cease-fire, which he said would head off the attack, BBC Television reported.
He then headed back to the Russian military command to ensure the relative peace would hold. Lebed's negotiations with top separatists resumed this morning in the southern village of Noviye Atagi.
''We sit down to talk with a clear intent of agreeing on something useful. It's high time to end this slaughter,'' Lebed said, according to the Interfax news agency.
Hundreds of Russian soldiers have been killed and at least 1,000 wounded in the rebel assault on Grozny this month.
Maskhadov endorsed Lebed's mediation efforts, according to ITAR-Tass. Rebels were still determined to defeat Russia but ''we're trying to do all we can to save face for each other,'' he was quoted as saying.
Some rebel spokesmen voiced optimism that Lebed and Maskhadov would sign a document today that ''will end the war in the republic, once and for all.''
Hundreds of heavy artillery shells had slammed into downtown Grozny on Wednesday. Salvos from multiple rocket launchers, bombs from jet fighters and rockets from helicopter gunships combined into a ferocious bombardment that could be heard 20 miles away.
Clashes continued overnight, with the Russian command reporting six Interior Ministry troops killed in a rebel attack in Grozny. The command also reported heavy sniper fire.
The acting commander who issued the ultimatum Monday night, Gen. Konstantin Pulikovsky, on Wednesday turned Russia's Chechnya operation back over to Lt. Gen. Vyacheslav Tikhomirov, who had been on vacation.
Tikhomirov's failure to lift the ultimatum stirred panic, anger and worldwide calls for Moscow to call it off. President Clinton sent Yeltsin a letter asking that the assault be averted.
Pulikovsky was publicly reprimanded Wednesday by Defense Minister Igor Rodionov and criticized by Lebed, whom Yeltsin put in charge of ending the war.
Yeltsin has remained largely out of the picture for two months with what the Kremlin calls fatigue and observers say is likely a recurrence of heart problems. His press secretary was quoted as saying the president would be back at work in Moscow today.
In all, more than 30,000 people have been killed since Moscow sent in troops in December 1994 to end the southern republic's independence bid.
=A9 Copyright 1996 The Associated Press