Defence Secretary George Robertson said RAF aircraft would be used to ferry emergency supplies to countries across Kosovo's borders sheltering refugees.

Eight further Tornado GR7s are also to be deployed in the bombardment of Serbia, Chief of the Defence Staff General Sir Charles Guthrie said.

BBC Correspondent George Eykyn reports on the morning's defence briefings

RAF Harriers on Tuesday also flew their first daylight missions since air strikes against Serbian targets began.

The Ministry of Defence briefing gave fresh instances of some of the atrocities Nato believes are being carried out in Kosovo by Serb forces.

The Russian prime minister is holding talks in Belgrade

Mr Robertson said four prominent Albanians, including the editor-in-chief of an Albanian language newspaper, were murdered on Sunday.

International Development Secretary Clare Short detailed the aid effort Britain is supporting for the ethnic Albanians who have escaped death but been forced out of their homes and villages.

She said tents and blankets would be flown to the 60,000 refugees already in Albania, plus the further 90,000 expected, while the UK would give £500,000 to the Red Cross.

The briefing came as Russian Prime Minister Yevgeny Primakov held talks in Belgrade aimed at finding a diplomatic means to stop the Nato bombing.

Foreign Secretary Robin Cook: "No sign Belgrade will accept a deal"

But UK Foreign Secretary Robin Cook insisted beforehand that a ceasefire by Serb forces would not be enough to stop the offensive.

"Certainly, we could not accept simply Milosevic calling a ceasefire leaving him in control of the territory which he's cleansed of the Kosovo Albanians.

"Any settlement now must involve the ability of those refugees to return in security, free from fear, with an international guarantee, to their homes."

If Mr Primakov could persuade Serbian President Slobodan Milosevic to accept the deal reached at the Rambouillet talks "that would be welcome", Mr Cook said.

"I see no sign at present that Belgrade is willing to do that," he added.

Nato bombing will continue, the allies say

Mr Cook said President Milosevic would have to accept an international military presence on the ground to police any peace accord.

"I think it would be extremely difficult to assemble any credible military force that did not include the 19 member states of Europe," he told BBC Radio 4's Today programme.

UK Prime Minister Tony Blair, speaking at Northern Ireland peace talks in Belfast, vowed to step up the attacks on Serb forces.

"We must now intensify the bombing campaign against Milosevic. I've spoken last night and this morning to both President Clinton and Javier Solana, the Secretary General of Nato.

"We are absolutely at one on this, the answer to what is happening is to intensify the attacks.

"It is to get in and hit Milosevic and his murderous thugs very, very hard. This is what we intend to do.

"There are risks to our forces. And, as I said when this campaign began, there are also risks to Kosovo Albanians."

The foreign secretary rejected criticism from those, including the Scottish National Party leader Alex Salmond, who blame Nato's actions for the exodus of ethnic Albanians from Kosovo in the past week.

"The refugees are not fleeing from the Nato bombs. It is not the Nato bombs that are destroying their, homes, burning their villages and putting pistols to their heads," he said.

George Reid defends SNP leader Alex Salmond's broadcast

But the SNP's constitutional affairs spokesman, George Reid, insisted Mr Salmond had spoken for many people.

"What has happened is that a disaster in Kosovo has now been turned into a humanitarian catastrophe of enormous proportions," he said.