At least 50 people have been killed in three car bomb blasts in the centre of the Iraqi capital, Baghdad, police say.

More than 80 were wounded when the three cars exploded in quick succession in a busy shopping area of the city.

The violence came as Iraqi and US forces raided insurgent strongholds in the city of Baquba, arresting more than 30 suspected insurgents.

Meanwhile, a top Shia leader who is due to meet President Bush rejected calls for an international forum on Iraq.

Abdel Aziz al-Hakim, the leader of the Supreme Council for Islamic Revolution in Iraq (Sciri), described the suggestion by United Nations Secretary General Kofi Annan as "unrealistic, incorrect and illegal".

Market blast

The blasts come only two days after US President George W Bush met Iraqi Prime Minister Nouri Maliki to discuss ways of tackling the sectarian violence.

The explosions occurred in the predominately Shia al-Sadriya area of the city.

The bombs were about 100m apart and exploded almost simultaneously, police Lt Ali Muhsin told the Associated Press news agency.

A witness said the blasts struck a vegetable market packed with women shoppers.

"The first explosion shook the area and a large piece of shrapnel landed near me. I saw people carrying bodies and dazed people running in all directions," the witness told Reuters news agency.

The BBC's Andrew North says this is almost certain to be seen as another sectarian attack.

It is the kind of incident that residents of Baghdad have been fearing ever since the bombings in the Shia Sadr City district just over a week ago which killed more than 200 people, our correspondent adds.

Elsewhere in and around Baghdad nine people were killed on Saturday, including a policeman who died when gunmen opened fire on a checkpoint outside west Baghdad's main Yarmouk hospital, Reuters news agency reported.

Iraqi police are also investigating a crash south of Baghdad that left some 20 people dead and several injured.

A truck traveling at high speed ploughed into commuters waiting at busy bus station.

Conference 'unacceptable'

UN Secretary General Kofi Annan said last week that it could be helpful to hold an international conference outside Iraq bringing together all the country's political parties to discuss ways of halting the escalating violence.

But Mr Hakim said Iraq's problems needed to be solved at home, adding that only the government of Prime Minister Nouri Maliki was qualified to find a solution to the conflict because it had been democratically elected.

"This government was formed on the basis of a coalition and it is therefore unacceptable for the Iraqi people that these questions should be debated at international conferences," said Mr Hakim, whose group holds a majority of seats in the Iraqi parliament and has close ties with Iran.

Its former military wing has been accused of involvement in sectarian violence.

Mr Hakim is due to meet Mr Bush in Washington on Monday to discuss ways of ending the violence.

Photo caption

Smoke rising from the scene of the blast