Russia's special Balkan envoy, Viktor Chernomyrdin, told reporters in Rome that his country and the West had moved closer together on the issue of a political solution to the war between Nato and Yugoslavia.

However, the US's announcement that it was deploying 10 more B-52 bombers in the region suggested no solution was imminent.

The BBC's Brian Hanrahan: "Nobody here is hopeful of an early agreement"

American Defence Secretary, William Cohen, said the B-52s and 30 tankers would be leaving shortly to "join the forces in Europe in order to intensify that campaign".

"We will start to attack for more hours, more targets and from more directions," he said.

Speaking at the Pentagon, he also said the US was in favour of using force if necessary to stop oil supplies getting through to Serbia - a view opposed by France.

Serb TV bombed off air

Nato also showed its determination not to let up until all its demands were met - carrying out heavy bombing raids on Belgrade.

Eyewitnesses said the Yugoslav army's main headquarters was hit by several bombs. One report said three people had died in the attack.

Nato also reportedly hit the defence ministry and a police building in central Belgrade.

Serbian state television, RTS, went off air in the middle of its late-night evening news bulletin as its main transmitter at Mount Avala was hit.

A BBC correspondent in Belgrade says Nato has made RTS installations one of its main targets, accusing it of pumping out war propaganda.

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

European talks

On the diplomatic front, Mr Chernomyrdin met Italian Prime Minister Massimo D'Alema in Rome on Thursday after inconclusive talks with German Chancellor Gerhard Schröder in Bonn.

The BBC's John Simpson: "Politicians are starting to think about life after Milosevic"

Mr D'Alema said he felt that there was movement in the negotiations and there was cause for hope.

Mr Schröder also reported "movement" in diplomatic efforts towards peace.

Mr Chernomyrdin is due to return to Belgrade on Friday for another round of negotiations with Yugoslav President Slobodan Milosevic.

The Russian envoy is expected to present Yugoslavia with "concrete proposals".

His plan includes a halt to Nato air strikes, followed by a withdrawal of Yugoslavian forces from Kosovo and autonomy for the province.

He has also said the refugees from Kosovo must be allowed to return home.

But Nato has insisted it will not halt the air strikes until Yugoslav forces pull out of Kosovo and are replaced by a peacekeeping force including Nato troops.

The US civil rights campaigner Jesse Jackson is also expected to meet Mr Milosevic, on Saturday, to try to free three captured US soldiers.

Reverend Jackson, who drove to Belgrade despite White House disapproval, said he also hoped to meet the three servicemen.

He said if the men were released it might provide a "window" for the various sides to "move gracefully and with dignity, towards the bargaining table".

However the Clinton administration urged him to tell Mr Milosevic there could be no link between halting Nato air strikes and the release of the soldiers

'Working together'

In Moscow, United Nations Secretary-General Kofi Annan met President Boris Yeltsin to discuss Russia's role as a peacemaker.

South African President Nelson Mandela, who was also in Moscow, was reported to have agreed to "help mediate in the crisis."

Mr Mandela criticised both Yugoslav President Slobodan Milosevic and Nato, accusing both sides of killing innocent victims in the conflict.

The Greek and Canadian foreign ministers were also in Moscow for talks about Kosovo.

The United States Deputy Secretary of State, Strobe Talbott, moved to London after "extremely intense and constructive" talks in Moscow with the Russian Foreign Minister Igor Ivanov.

Mr Talbott said he was convinced the US, Russia and other countries could work together to bring peace to the region.

Major strike on Montenegro

Montenegrin Government held an emergency meeting following Wednesday night's heavy Nato bombing raids near the capital, Podgorica.

The attack was the third on Montenegro in 24 hours, with 30 bombs dropped on a military airfield target near the capital.

A Nato spokesman said the raid was planned after the discovery that the Yugoslav military had moved forces there, though Nato intended to spare Montenegro as much as possible.

Anti-aircraft guns fire over Belgrade

Nato has also admitted that a missile hit a residence in the Bulgarian capital, Sofia.

Nato spokesman Jamie Shea said a jet fighter launched the missile "in self defence", but that it strayed from its target and unintentionally landed in Sofia - about 60km from the Yugoslav border.

It was the third missile to strike Bulgarian territory during the five-week air campaign.

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