GROZNY -- Fighting raged between Chechen rebels and Russian forces Thursday, making Defense Minister Pavel Grachev worry that the violence could spoil a giant party planned for more than 50 world leaders in Moscow next week.


Grachev, quoted by Itar-Tass, said all but a few rebels had been crushed completely, but they could still "spoil the festive mood" of the V-E Day celebrations that heads of state from around the world are scheduled to attend.


Grachev told Interfax he had no plans to talk peace with Chechen field commanders until after the end of the Victory Day celebrations.


In a clear indication that the fighting in the North Caucasus region is far from over, the Kremlin decided to send in marines specially trained to fight guerrillas, Interfax said.


Fighters loyal to rebel Chechen leader Dzhokhar Dudayev, defying President Boris Yeltsin's unilateral truce of April 28, have warned they plan a big offensive on the capital Grozny to coincide with the celebrations.


Renewed bloodshed in the region could seriously embarrass Yeltsin before his foreign guests, who have criticized Russia's military operation, and increase tensions with the West.


The rebels stepped up the pressure Friday by mounting attacks on Russian troops in the ruins of Grozny.


A Defense Ministry spokesman in Grozny told Interfax that Russian forces had been attacked by Chechen fighters at least 14 times overnight and forced to return the fire.


Major Alexander Karev, commander of Russian troops in the city, said battles raged all night in the northwest Leninsky district. About 30 separatist fighters had been killed but the Russians had suffered no major casualties, he said.


Chechens and Russians have frequently exaggerated both casualty reports and reports of military success.


Interfax said Moscow had positioned special marines from the Baltic Fleet about 20 kilometers south of Grozny.


It quoted the Russian military press center in Grozny as saying that Chechen military leader Aslan Maskhadov had promised a big attack on the 50th anniversary of V-E Day.


"He [Maskhadov] promised to make the night from May 9 to May 10 a night of fireworks," the press service said. The head of Chechnya's Moscow-backed opposition joined the criticism of Russia's use of firepower in Chechnya, calling its methods "severe and tragic" and accusing it of using banned weapons and bombing civilians.


Umar Avturkhanov, head of the Moscow-backed Committee of National Unity, said, "We consider the further escalation of military actions inadmissable."


The Segodnya newspaper said Yeltsin's truce offer was aimed entirely at Western leaders who have criticized the campaign, and was not intended to appease the separatists.


It said the Chechens had stepped up their fight to show the West they were still a force to be reckoned with.


"Russian troops are bogged down in Chechnya, and an unconditional and inglorious withdrawal of forces is absolutely unacceptable to the people who sent a badly prepared army [to Chechnya] in mid-December," it said.