Chechen officials said at least 32 people were killed in air and artillery attacks on Grozny. Russian artillery also continued pounding Chechen positions around the second-largest city, Gudermes, in the east, and Bamut, in the west.

Rebel commander Shamil Basayev told Reuters news agency: "The Russians have adopted the tactic of killing from on high, from planes that cannot be hit, dropping bombs and rockets that kill civilians."

Russia's army headquarters at Mozdok, just outside Chechnya, was quoted as saying troops had fired tactical missiles at the outskirts of Grozny. Itar-Tass said they had shot two volleys of surface-to-surface missiles.

The BBC's Orla Guerin: "Moscow is fighting this war with everything it has got"

However the Russian Defence Ministry in Moscow denied the troops had fired the missiles and said warplanes had bombed a series of villages to the west and south of Grozny.

Almost 200,000 people have fled the bombings so far - most of them heading for the neighbouring province of Ingushetia.

Russia says almost 7,000 people have crossed into Ingushetia during the past two days. The BBC's Orla Guerin, who was at the border, says many of those fleeing described the Russian offensive as relentless.

Thousands were still queuing to cross the border on Saturday, most of them leaving Chechnya but others were hoping to return home from Ingushetia to rescue relatives still there.

Click here to see a map of the region

Russia on Saturday tried to encourage refugees to return to Russian-controlled parts of Chechnya.

Emergency Situations Minister Sergei Shoigu said the government had chosen 17 towns and villages in Chechnya it considers safe for the refugees' return. He promised that Russian forces would guarantee their safety.

Putin: "A bandit enclave"

However Russia's prime minister has ruled out an end to the bombing until all "terrorists" were destroyed.

In an apparent rebuff to international demands for a negotiated settlement, Vladimir Putin said Russia had to liquidate a bandit republic which supported terrorism and the black market.

He told the Kommersant daily newspaper: "If the so-called Chechen problem is not solved, if the hot spot of banditry and terrorism in the rebel republic is not destroyed, then the Caucasus will be lost and a 'sanitary zone' will have to be created around Moscow."

Chechen President Aslan Maskhadov was quoted as saying he was ready for talks to end the fighting, which he said had killed over 4,000 civilians.

"I am ready for any kind of talks which could stop the war and stop the killing of peaceful people," Interfax news agency quoted him as saying.

Telephone diplomacy

The UK stepped up pressure on Russia for an end to the bombing when Foreign Secretary Robin Cook telephoned his counterpart Igor Ivanov to express his concern about the overall situation in Chechnya, especially the plight of the refugees.

"He asked for early access to the area for humanitarian organisations, particularly to meet the needs of the refugees," the Foreign Office said.

"Mr Cook called for a halt to the fighting and told Mr Ivanov that he was concerned about the lack of a political strategy."

The UK foreign secretary's initiative follows a letter from Prime Minister Tony Blair to his Russian counterpart, expressing concern about civilian casualties and the plight of refugees.

But the head of Russia's ministry for mass media told ORT television that the press was exaggerating the refugee crisis and said many of the pictures from the border were "staged".

"As soon as a camera comes close, two or three women start to cry 'freedom for the Chechen people, when will you stop killing us and when will you stop torturing us'," he said.

"As soon as the cameras are turned off, all these statements stop."