Officials in Moscow said the delay was to allow Russian envoy Viktor Chernomyrdin and EU representative Martti Ahtisaari to continue their own talks in Bonn before leaving.

No details were given of the talks or how long their departure would be delayed.

The Yugoslav authorities suffered a setback at the International Court of Justice in The Hague on Wednesday. The court rejected an attempt by Yugoslavia to halt Nato air stirkes, which it says violate international law.

At a hearing in The Hague last month, Serbia argued the use of force over the conflict in Kosovo was not justified by international law.

Peace trip 'still on'

The BBC's Jon Leyne: "Nato certainly shows no sign of compromise"

Mr Chernomyrdin and Mr Ahtisaari are thought to be finalising a peace offer, on which bothe the Nato alliance and Russia can present a unified front, based around a plan worked out by the G8 nations last month.

The BBC's Moscow Correspondent, Andrew Harding, says an official at the office of Viktor Chernomyrdin said as long as talks in Bonn were continuing, one must assume the trip to Belgrade is still on.

But should negotiations be called off, and Mr Chernomyrdin return to Moscow, it would become clear the whole peace process had been delayed.

If the mission goes ahead, it will be the first time during the crisis that Yugoslav President Slobodan Milosevic has faced a joint team from Russia and the EU.

BBC Diplomatic Editor Brian Hanrahan: "Signs of slippage in Belgrade"

For their part, the US Secretary of State, Madeleine Albright, and her Italian counterpart, Lamberto Dini, reiterated that they would not compromise over Nato's demand that its troops be at the core of a peacekeeping force in Kosovo.

There is still no indication that Belgrade would allow a Nato-led peace-keeping force to enter Kosovo.

Another blunder

World Affairs Editor John Simpson: Most people believe Nato deliberately targets civilians

News of diplomatic progress came after Nato admitted its aircraft had mistakenly bombed Albanian army forces on the Albanian side of the Kosovo border, destroying a guard box.

The incident followed a series of Nato air strikes in the Morina border area as intense fighting continued between Kosovo Liberation Army guerrillas and Serbian forces.

(Click here to see a map of latest Nato strikes)

Jeremy Cooke reports: "This was another highly visible Nato mistake"

Although none of the Albanian forces appeared to have been killed, the blunder was one of Nato's most embarrassing, with several waves American A-10s dropping laser-guided bombs.

Albanian soldiers guarding the Morina border point fled, apparently unsure whether the attackers were Serbian or Nato.

The border has seen three days of heavy Serbian shelling following attempts by the KLA to open a supply route along the border. Hundreds of refugees have passed through the area in recent weeks.

Nato spokesman, Jamie Shea: "We shall keep this up until Mr Milosevic meets the conditions of the international community"

Nato air strikes are reported to have reduced in intensity overnight on Tuesday and early Wednesday morning, ahead of the expected arrival of the peace mission.

Sites in and around Belgrade were hit on Tuesday evening but the city was reported to be calm early on Wednesday.

The town of Prizren was reported to have come under heavy attack on Tuesday, with at least 70 missile strikes according to the Yugoslav news agency Tanjug.

Also targeted overnight were a radio relay in Ruma, and an army barracks near Kursumlija, 190 km (120 miles) south-east of Belgrade.

Yugoslav military chief dies

In Yugoslavia itself, the military has taken the unusual step of reporting the death of the air force deputy chief of staff.

General Ljubisa Velickovic: "Died in the line of duty"

The Yugoslav military information service said on Tuesday that General Ljubisa Velickovic had died "in the line of duty" while inspecting military units in "the first line of defence" against Nato air attack.

It is not clear whether the death was the result of a Nato air attack. The military as a rule does not report casualties among the armed forces.

Russia hopeful for peace

Nato's raid over Albania followed reports of three Nato blunders in the past two days.

Nato has admitted that a bomb went astray during an attack on an army barracks in the southwest Serbian town of Novi Pazar.

The Yugoslav authorities said 23 people were killed when Nato missiles hit an apartment building in the town.

Nato spokesman Jamie Shea said that five out of six weapons hit the army barracks, but one went astray, overshooting the target by about 60 metres, and may have hit residential buildings.

He said Nato could not confirm any civilian casualties but regretted any unintended damage.

At least 28 civilians were reported killed in two other attacks in the previous 24 hours.

• Court rejects Yugoslav bombing case
• Nato bombs fall on Albania
• Civilian deaths 'necessary price'
• Albania warns of Serb tank advance
• Times journalist 'amazed to be alive'

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