Nine Iraqi soldiers have been killed in two separate explosions targeting their patrol south-eastern Baghdad, Al Jazeera has learned from Iraqi police.

Nine other soldiers were wounded in the blasts.

In separate incidents on Wednesday the Iraqi Interior Ministry says five Iraqi civilians were killed when a roadside bomb exploded as a police patrol passed in south Baghdad.

A second bomb aimed at a bus carrying workers to an oil refinery in the Dura neighbourhood wounded another five people, ministry officials said.

The attacks took place a day after the US military announced the death of another soldier, bringing US losses in October to 94, the fourth biggest monthly toll since the 2003 invasion.

Yemenis held

US forces also announced the capture of two men in south Baghdad they said were from Yemen and might be members of Osama bin Ladin's al-Qaida network.

The men are "suspected members of a Yemeni branch of al-Qaida who were on a reconnaissance assignment in Baghdad", the military said. "Both were in possession of Yemeni passports."

The men "admitted to being from Yemen", said Captain Matthew Wheeler, a US intelligence officer.

"There's a lot of circumstantial evidence against the detainees, and that will solidify as we examine the evidence more closely."

Anti-US fighters have stepped up their use of roadside bombs even as US troops have devised ways to blunt their effectiveness, General Peter Pace, the new chairman of the US Joint Chiefs of Staff said.

Speaking at the Pentagon on Tuesday, Pace said the high US death toll for October was in part because there were more US troops than usual in Iraq for a 15 October referendum on a new constitution.

That also drew increased insurgent violence intended to disrupt the vote, he said.

Biggest problem

Pace acknowledged that roadside bombs were still a problem despite huge investment in US armoured vehicles over the past year.

"Between the increase in armour and the changes in tactics, techniques and procedures that we've employed, the numbers of IED [improvised explosive device] attacks that have been effective has gone down and the number of casualties per effective attack has gone down," he said.

"That said, there are more overall IED attacks by the insurgents, and we are working on that problem," General Pace added.

The use of shaped explosives capable of piercing armour, more advanced timers and detonating devices and more sophisticated tactics have accompanied the rise in IED casualties.

PHOTO CAPTION

Iraqis gather at the site where a car bomb exploded in the southern city of Basra. (AFP)