•  Click here for live coverage
  
• Click here for map of main targets

All Nato aircraft are reported to have returned safely to their bases after a second night of bombings in Yugoslavia.

The onslaught was said to be significantly heavier than Wednesday's bombardment.

Nato faced condemnation from some countries led by Russia, and signs of possible splits within its own ranks over a political endgame following strikes.

But despite the concerns, US President Bill Clinton and his Secretary of State Madeleine Albright are set to speak directly to the people of Yugoslavia in a satellite-broadcast address at 0730GMT Friday.

Ms Albright will speak in Serbo-Croat and outline Nato's arguments.

Nato had earlier warned Yugoslav President Slobodan Milosevic that his armed forces would be destroyed unless he backed down over Kosovo.

Loud blasts were heard near Belgrade and witnesses said there were at least 15 explosions around Kosovo's capital, Pristina. Air-raid sirens sounded in both cities.

Reported targets included barracks in Urosevac in southern Kosovo, an airport at the city of Nis, a military supplies factory and communications and air defence centres.

Bombs fell around Golubovci airport outside Montenegro's capital Podgorica and explosions were heard near Danilovgrad where munitions dumps are located.

Reports said a television station in central Serbia broadcast an appeal for surgeons to report for duty immediately and for blood donors following the first raids.

Cruise missiles

More than 100 Nato planes, including US stealth bombers, F-15 and F-16 fighter jets and Sea Harriers, took off in waves from bases across Europe.

The BBC's Brian Hanrahan: "Nato officials warn this will be a sustained campaign"

Four US warships also launched a barrage of Tomahawk Cruise missiles from the Adriatic Sea.

Lieutenant Commander Yvette Brownwahler, of the USS Gonzalez, called it a "major cruise attack" - far heavier than the warships' opening volleys on Wednesday night.

Reports that all allied aircraft had returned safely conflicted for the second night running with reports by Serb media which said two Nato planes had been shot down.

Bombings to intensify

As Operation Allied Force resumed, Yugoslavia confirmed it had broken off diplomatic relations with the United States, Britain, France and Germany.

Earlier in the day, Nato's supreme allied commander in Europe, General Wesley Clark, threatened to destroy Serb forces unless President Milosevic stops his attacks on ethnic Albanians and signs a peace deal for Kosovo.

General Clark: We're going to attack, disrupt, degrade, devastate

He said three Yugoslav planes were destroyed in the first night of strikes and at least 40 targets were struck.

The attacks in the Belgrade area were the first on a European capital since 1945.

US Defence Secretary William Cohen warned the bombing campaign against Serb targets would intensify but said there was still "an opportunity to pursue the path of peace".

Madeleine Albright said diplomatic channels between Nato and Belgrade were still open. But she warned President Milosevic not to spread the conflict beyond Yugoslavia's borders.

Yugoslavia said the bombardments had destroyed the international peace plan for Kosovo but Belgrade remained ready to accept autonomy for the Serbian province.

But in a conflicting statement on UK television, Yugoslav Deputy Prime Minister Vuk Draskovic said they would cease all operations against the ethnic Albanians if Nato stopped its bombing.

However, reports said Serb forces were continuing their offensive against Kosovo Albanians, despite the launch of Nato strikes.

'Ten civilians killed'

Yugoslav authorities estimated around 10 civilians were killed in Wednesday's Nato raids and another 60 injured, but declined to give details of any military casualties.

The Yugoslav army said 40 targets were hit in three hours including five airports, five barracks, communications and command positions.

Russian warnings

Russia has submitted a resolution to the UN Security Council demanding an end to the Nato attacks.

President Boris Yeltsin said Nato's aggression was ''a gross mistake'' and warned the US it would be held to account for the air strikes.

Reports say the Security Council on Yugoslavia is planning to meet on Friday to vote on the resolution.

China and India have also condemned Nato actions.