Russian soldier loading a howitzer to the east of Grozny

The official said that Chechen fighters could not compete with Russian military hardware. He said Moscow was too strong to defeat in a traditional war.

But he said the Chechens would make it impossible for Russian troops to travel safely around the countryside and would fight on until the last of them had gone.

Correspondents in the region report that the Russians have so far not got bogged down in close engagements.

They have instead relied on long-range weapons like the GRAD surface-to-surface missiles, which is not very accurate but capable of devastating large areas of territory.

On Thursday, Achkhoi-Martan, near the border with Ingushetia, was the second major Chechen town to surrender, Russian officials said.

Last week, federal forces entered Chechnya's second city, Gudermes, without opposition.

European security summit closes

Friday's bombardment came as Russian and Western leaders adopted a declaration on Chechnya and a charter on European security at the Istanbul summit of the Organization for Security and Co-operation in Europe (OSCE).

Correspondents believe the watered-down statement is unlikely to have much impact on the Russian campaign in the breakaway republic.

Russia is already violating the new charter limiting the number of conventional military forces across the continent.

The declaration on Chechnya stated: "We agree that a political solution is essential and that the assistance of the OSCE would contribute to achieving that goal ... We welcome the agreement of the Russian Federation to a visit by the (OSCE) Chairman in Office to the region."

Russian officials made it clear that there would be no withdrawal of forces from Chechnya and ruled out a mediation role for the OSCE - a concession that Moscow had appeared to make in Istanbul on Thursday.

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