In an interview with Montenegro Television, which the prime minister hoped would also be seen by Serbs, he contrasted the leaders of the two republics.

Serbia and Montenegro are sister republics in the Yugoslav Federation, but have often fallen out in the past two years.

Mr Blair described Serbian President Slobodan Milosevic as a "brutal bloody dictator".

Milo Djukanovic has "enormously increased the respect for Montenegro", Blair says

Montenegran President Milo Djukanovic had shown another path, by standing up for "civilised values", Mr Blair said.

"I think because of the stand that President Djukanovic has taken, then the sense of responsibility that we all have towards Montenegro is all the greater.

"The fact that you have stood out against Milosevic and refused to agree to his policy of ethnic cleansing has enormously increased the respect and support for Montenegro."

The UK prime minister promised support for Montenegro if reports of Belgrade plotting a coup there proved true.

"Milosevic must know that we stand ready to support the people of Montenegro so if he thinks that he can take you on, he will pay a very heavy price for that indeed.

"We want to do everything we possibly can to assist you through this and to protect you through it."

Mr Blair repeated his message that the Nato allies have no quarrel with the people of Serbia, or Montenegro.

"They have been our allies on many occasions, but we cannot allow in Europe, in one of the most sensitive places in the whole of the continent, a dictator to move people in their thousands, in their hundreds of thousands, from their homes, butcher them, maim them, torture them, then dump them on surrounding countries and sit idly by.

"If we were to do that, if we were to allow Milosevic to carry on with his policy of ethnic cleansing and not take any action to stop it, he would have felt free to do whatever he wanted in any part of the Balkans.

"We would have said we didn't have the courage, determination, the vision or the sheer basic humanity to act against it."

An anti-Nato demonstration in Montenegro

But Mr Blair stressed he had no desire to be involved in a war and wanted the conflict to cease.

"I don't want to be engaged in this action. I don't want to put British forces into this situation. I didn't want to have the whole power of Nato now utilised against the Serbian war machine.

"I didn't want any of this, I wanted peace talks to happen, I wanted a settlement to be hammered out and I wanted the people of Kosovo, Serbia and Montenegro to live side by side together.

"It is Milosevic that has provided this, he has provided it because he has a desire for total domination.

"Now we're confronted with that position we had to act.