President Vladimir Putin has insisted that Russia has the right to defend itself against cross-border attacks, in a speech which hinted at the threat of military strikes on neighbouring Georgia.

Mr Putin's comments - seen as the sharpest warning yet to Tbilisi - follow weeks of mounting tension between the two countries over the activities of pro-Chechen rebels along the Russian-Georgian border.

Russia accuses Georgia of allowing militants to shelter free from the law in its remote Pankisi Gorge area, while Georgia accuses Russia of bombing the area.

I am asking the military staff to provide proposals on whether it is possible and expedient to launch strikes

President Putin

The Russian army had now been asked to prepare proposals on attacking militants' bases in the gorge, Mr Putin said.

He said Russia had a right to self-defence under United Nations principles if Georgia failed to stop "bandit incursions" across the border.

"I am asking the military staff to provide proposals on whether it is possible and expedient to launch strikes on bases of terrorists reliably identified in intelligence operations," Mr Putin said, speaking in the Black Sea resort of Sochi.

"If the Georgian leadership cannot set up a security zone along the Georgian-Russian border... [and] fails to prevent outrages and incursions on Russia's neighbouring areas, we reserve the right to act in line with Article 51 of the UN Charter, which gives every UN member nation the right to defend itself on its own or collectively."

Last week, Mr Putin sent an angry letter to his Georgian counterpart, Eduard Shevardnadze, in which he accused Georgia of inefficiency in dealing with rebels.

The Georgian Government has sent troops to the area, and Mr Shevardnadze visited the gorge himself to try to demonstrate his commitment to tackling the problem.

But Moscow says the troops deployment has done little to solve the problem.

It believes up to 500 rebels are sheltering in the area.

Georgia, for its part, says Russia has violated its airspace.

Mr Putin said on Wednesday that the lawlessness in Pankisi was "poisoning our feelings of sympathy and respect for the Georgian people".

American officials have now publicly said they believe al-Qaeda agents may be operating in Chechnya.

The US Ambassador to Moscow, Alexander Vershbow, said on Wednesday: "We both have been confronting terrorism that has an international dimension, and I think we know that al-Qaeda has been involved in supporting the separatists in Chechnya."