Many casualties in Baghdad blast

The victims were labourers waiting for daily work

A bomb explosion in the Sadr City area of the Iraqi capital, Baghdad, has killed at least 30 people and injured more than 60, officials say.

The blast targeted labourers who had gathered for work early in the morning in Mudhafa Square, in the densely populated, largely Shia neighbourhood.

At least 50 people have died in other attacks in Iraq.

Meanwhile, the death of two US troops has taken US losses in October to 101 - the highest total since January 2005.

One of the troops, a marine, was killed on Sunday in combat in Anbar province, west of Baghdad, the US military said.

The other, a military policeman, was reportedly killed in eastern Baghdad.

More than 2,800 US troops have died since the invasion of Iraq in 2003. November 2004, when 137 US soldiers were killed, remains the deadliest month so far.

Iraqi Foreign Minister Hoshyar Zebari has said his government plans to ask the UN Security Council to extend the mandate of the US-led forces in Iraq.

Sadr City is, in effect, a Shia township Sadr City: Restive township

In an interview with Reuters news agency, Mr Zebari said it was vital for Iraq's security that foreign troops continued to operate under the mandate for a further year. It is due to expire at the end of December.

In other developments:

• Five car bombings kill at least 12 people and injure at least 20 in various areas of Baghdad

• Two police officers die in a suicide attack on a passport office in the northern city of Kirkuk

• Gunmen in Baghdad kill senior academic Isam al-Rawi, head of the university teachers' association in Iraq

• US National Security Adviser Stephen Hadley makes an unannounced visit to Baghdad, meeting Prime Minister Nouri Maliki

• The trial of Saddam Hussein over the killing of more than 100,000 Kurds resumes, but his chief lawyer walks out after the court refuses to allow foreign lawyers to attend

• The US Defence Department sets up a new media unit that will focus on getting the US message across online channels

  Meanwhile, an Iraqi delegation has met a newly-formed group of Iraqi exiles in the Jordanian capital, Amman, to persuade them to return to Iraq for a reconciliation conference in November.

  The exiles, who include former soldiers and members of Saddam Hussein's Baath Party, are said to have rejected the invitation, demanding that insurgents should be included in the talks.

  US cordon

  Iraqi authorities said Monday's blast in Sadr City appeared to have been caused by a device concealed in a rubbish bin by the roadside.

  

  "The bomb was hidden in a plastic bag. It's the third time that an attack has hit this place this year," a witness, Abu Zeinad, told the AFP news agency.

  There was no immediate indication who was responsible but suspicion will fall on Sunni extremists, the BBC's Hugh Sykes in Baghdad says.

  There have been several attacks like this before, killing dozens of casual labourers waiting for work, our correspondent says.

  Sadr City, with its population of about three million, is a stronghold of Shia cleric Moqtada al-Sadr, who heads the Mehdi Army militia.

  Meanwhile, US forces are continuing to operate roadblocks and patrols around Sadr City as they hunt for a kidnapped American soldier.

  A raid carried out in the district on Friday triggered brief clashes with Mehdi Army militia members.

  Reports suggest the abducted soldier is an Iraqi-American translator who broke US Army rules to marry a local woman.