Frequent clashes have taken place between the opposition and police

It was cancelled because KM Hasan, the man due to head the government, was ill, a presidential spokesman said.

Up to six people died as thousands took to the streets on Friday hours before outgoing PM Khaleda Zia's term expired.

The interim government is to organise elections in January, which the opposition fears Mr Hasan will rig.

Fresh violence broke out in a number of towns and cities as the handover ceremony, which had been scheduled to take place on Saturday, approached.

The opposition Awami League has threatened to paralyse the country if Mr Hasan takes office, with demonstrations and blockades of roads, railways and the country's main port.

Khaleda Zia said the transfer of power will go ahead

It says Mr Hasan, a retired chief justice, is a stooge of the ruling Bangladesh National Party (BNP) and cannot be trusted to run the supposedly-neutral interim administration tasked with organising the polls.

Mrs Zia promised to respect the constitution in a speech hours before her five-year term expired at midnight on Friday.

She appealed for calm across the country as fresh violence broke out in a number of towns and cities.

She promised the poll would be free and fair, and said the constitution would "safeguard a peace-loving and responsible nation".

It was a matter of "great regret" that talks with the opposition aimed at defusing the current crisis had not produced results, she added.

Major confrontation

There have already been sporadic outbreaks of violence, but the BBC's Roland Buerk in Dhaka says many people fear this is the calm before the storm.

Talks between the parties have so far failed

He says the transfer of power threatens to spark a major confrontation between the government and opposition.

On Friday, one person was killed in the eastern town of Brahmanbaria during clashes between supporters of the outgoing BNP and Awami League.

Another died in violence near Dhaka between followers of the BNP and newly-formed Liberal Democratic Party, which contains high-profile defectors from the ruling party.

A third person was killed in a clash in Khilgaon district, the United News of Bangladesh news agency reported.

More than 100 other people were hurt in the capital and elsewhere.

Boycotts

Bangladesh's politics is especially bitter because of the deep personal rivalry between Sheikh Hasina of the Awami League and Mrs Zia.

They have led the country in alternate terms since 1991 but have not spoken for years.

Parliament has been boycotted regularly by whichever party is in opposition, and a culture of street demonstrations has developed.

The BNP, about to leave power, is calling for its supporters to be ready to take on opposition activists in the streets.

Our correspondent says that there will be little the 25,000 police and security personnel deployed in the capital, Dhaka, can do as the powerful political parties try to enforce their dominance of the streets.