The Chinese authorities have backed the protests, saying they fully reflected the anger of the people.

Nato spokesman Jamie Shea said on Sunday that the embassy had been attacked because of "faulty information" about the nature of the building targeted.

The alliance's raids on Yugoslavia continued on Saturday night, but the capital was not reported to have been attacked.

(Click here to see a map of Saturday night's bombing)

Beijing Correspondent Duncan Hewitt: "This is not about to suddenly die down"

The hit on the embassy on Friday night killed at least three people - a female reporter for China's state news agency, Xinhua, another journalist and his wife.

Expressions of regret from Nato leaders appear to have had little impact in China.

As Sunday dawned in Beijing, thousands of protesters arrived at the US embassy - joining many others who had been there overnight, chanting anti-American and anti-Nato slogans.

The BBC's Jill McGivering: "The unleashed anger could be hard to contain"

The Chinese Government said it would support them as long as they remained legal.

BBC Beijing Correspondent Duncan Hewitt said the authorities even seemed to be encouraging the demonstrations.

Students were bussed in from university campuses, and the mood was fanned by angry comments in the morning papers.

Stones and rocks were hurled at the US Embassy on Saturday

The official People's Daily newspaper implied that the bombing had been no accident, and said Nato was accountable for spilling Chinese blood.

However the authorities vowed to protect foreign diplomats on its soil after protesters on Saturday threw stones at US and UK embassies and consulates across the country.

The residence of the US Consul General in the south-western city of Chengdu was stormed and partially burned.

More bombing raids

Calls for an end to Nato's air campaign appear to have had little effect on alliance chiefs.

The BBC's Mike Williams in Belgrade: Many people were on the streets

Serbian state radio said overnight attacks on relay transmitters put state and private television and radio off the air in a number of areas.

A post office at Uzice - south of Belgrade - was also reported to have been destroyed, cutting off local telephone links.

Other targets included a piping factory in Valjevo, which Nato said made munitions.

Serb reports said attacks during Saturday hit a bridge close to the Greek consulate in the southern Serbian city of Nis, injuring seven people.

The official Yugoslav news agency Tanjug said 13 people were wounded in an attack on Kragujevac, southeast of Belgrade.

Deep regret

The Beijing protests appear to have been well organised

US President Bill Clinton expressed deep regret for the embassy strike, but said it had been an accident, not a barbaric act.

He echoed the words of Nato Secretary-General, Javier Solana, saying the incident would not deter the alliance from continuing its air campaign.

Correspondents say the attack will make it harder to avoid China's veto during any peace talks at the United Nations Security Council.

Diplomatic track continues

Diplomacy continues: Ibrahim Rugova meets Gerhard Schröder

As the political fallout continued, Russia's special Balkans envoy, Viktor Chernomyrdin, said the conflict had to be resolved by political means as quickly as possible.

He was speaking after talks in Bonn with the German Chancellor, Gerhard Schröder, about the G8 countries' peace plan for Kosovo.

Both men held separate talks with Kosovo Albanian leader Ibrahim Rugova.

Mr Chernomyrdin said that following his talks he was expecting to return to Moscow and not to Belgrade as had previously been suggested.

• Embassy strike: What went wrong
• Picture gallery: Fury at embassy bombing
• UN moves to ease refugee burden
• Calls to investigate Agani killing
• Embassy bombing dominates Serb media

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