World highlights

• Thousands of American troops searched for three US soldiers missing in Iraq after an ambush in which al Qaeda said it seized crusader forces, while a suicide bomber killed 50 people in the Kurdish north. The self-styled Islamic State in Iraq, a group led by al Qaeda, said in an Internet posting it was holding soldiers who survived an attack south of Baghdad in which the US military said four US troops and an Iraqi army translator were killed.

• The US and Iran will meet in Baghdad in the next few weeks to discuss Tehran taking a productive role in Iraq's security, the White House said. US Ambassador to Iraq Ryan Crocker will represent the US, which has accused Iran of backing Shi'ite militia in Iraq and seeking an atomic bomb. Tehran denies both charges.

• Four Palestinians were killed in Gaza and Hamas said 15 supporters were abducted in the deadliest outbreak of factional fighting in the coastal strip in months, Palestinian officials said. Gunmen killed a senior commander of al-Aqsa Martyrs Brigades and another member of the Fatah-linked militant group in an attack the Brigades blamed on the rival Hamas movement.

• The Pakistani government authorised paramilitary troops to shoot anyone involved in serious violence in Karachi, where 37 people have been killed over the past two days, an official said. On Saturday, 34 people were killed and more than 130 wounded in the country's worst political street violence in two decades, sparked when Pakistan's suspended top judge tried to meet supporters in the southern city.