RUSSIANS STYMIED IN CHECHNYA : DESPITE INCREASED OFFENSIVE, MILITARY UNABLE TO TAKE OVER CAPITAL.

Byline: Michael Specter The New York Times

On one of the most violent days of the 20-month war in the secessionist republic of Chechnya, Russian troops fought desperately but in vain Sunday to regain control of the regional capital, Grozny.

Television showed a city in flames Sunday evening as the bodies of dozens of young Russian soldiers lay where they fell in the muddy streets. Thousands of refugees - many dragging their possessions in the sweltering heat - fled the city on foot. President Boris N. Yeltsin convened a meeting of his top advisers in the Kremlin and then sent his national security adviser, Alexander Lebed, to the region for consultations.

``Radical measures must now be taken to settle this problem,'' said Prime Minister Viktor Chernomyrdin after the meeting. The president ordered Chernomyrdin to find the cause of the ``gross miscalculations'' that led to the successful rebel offensive, which began last Tuesday.

``We will proclaim a state of emergency in Chechnya if that is what we need to do,'' Chernomyrdin said after the meeting, although it was unclear how that could affect the fighting there.

The war Sunday appeared to reach an appalling new low for Moscow. Russian military officials, long known for presenting low estimates of their losses, said that at least 200 soldiers had died and more than 800 had been wounded since the offensive, timed to coincide with Yeltsin's inauguration last week, began. By comparison, after the first eight months of the war, Russian leaders said they had lost no more than 1,000 servicemen. Nobody knows how many separatists and civilians have died in the fighting this past week. By most estimates, at least 30,000 people, mainly civilians, have died since the war began.

The pace and character of the conflict - after months of quasi-peace followed by fierce Russian bombing raids and rebel counterattacks - has again attained the sustained viciousness with which it began.

After dozens of truces and many attempts at peace, including a pledge by Yeltsin to end the fighting, the war still remains visibly impossible to resolve: The rebels are fighting for the independence of Chechnya, one of the many republics of the Russian federation. Russian leaders say that Chechnya can never be anything but a part of Russia. It is a battle that has been waged with different levels of intensity for more than 300 years, when Russia first rolled across the Caucasus and colonized the region.