A series of explosions in mostly Shi'ite areas of Baghdad Wednesday has killed more than 170 people and injured scores more. The attacks deal a blow to a two-month-old security plan in the capital. From northern Iraq, VOA's Margaret Besheer has more.

Aftermath of the Sadriyah market attack, 18 Apr 2007

Late Wednesday Prime Minister Nouri al-Maliki ordered the arrest of the Iraqi army colonel who was in charge of security in the region around the Sadriyah market. The colonel's name was not given.

Police say among the dead were several construction workers who had been rebuilding the mostly Shiite marketplace after a bomb destroyed many shops and killed 137 people during an attack there last February.

About an hour earlier, a suicide car bomber detonated at a police checkpoint at an entrance to Sadr City, the Shiite slum in eastern Baghdad that is a stronghold for radical cleric Moqtada al-Sadr. Several cars at the checkpoint caught fire in the blast and dozens of people were killed and injured.

Earlier, a parked car exploded near the Abdul-Majid hospital in the central Karradah neighborhood. Police said several people were killed and injured. The hospital and several other buildings were also damaged in the blast.

Another explosion occurred in the Rusafi neighborhood. Police say a bomb left on a minibus exploded, killing and injuring several people.

It was the worst day of violence since the Iraqis and Americans launched a new security plan in the capital in mid-February. U.S. military officials have said overall sectarian killings are down, but high-profile car bombings, like Wednesday's, continue to be a problem.

In an interview with VOA's Kurdish service from the U.N. conference on Iraqi refugees in Geneva, Iraqi Foreign Minister Hoshyar Zebari condemned the bombings.

"I think this carnage today in Baghdad streets and the targeting of innocent workers and civilians by car bombs, by the terrorists, in fact was an indication of how desperate they are," said Hoshyar Zebari. "In order to draw attention - to try and show that the Baghdad security plan is not working. The truth is, it is the opposite. In fact, because it is working, they are getting desperate to target civilians."

Zebari said the attacks would not undermine the government's resolve to continue implementing the security plan. And he said it would be several months before the impact of the security plan is apparent.

Meanwhile, in contrast to the violence in Baghdad, British military officials transferred security responsibility for the southeastern Maysan province to Iraqi control. It's the fourth province to be transferred.

The British commander in southern Iraq, Major General Jonathan Shaw, said the transfer is a sign of growing Iraqi capabilities.

"I am optimistic because the support of the multi-national forces will continue to facilitate the people of Iraq along the road to self-reliance," said General Shaw. "And I am optimistic because the examples of al-Muthanna, Dhi Qar, Najaf and now Maysan will demonstrate to the rest of Iraq what can be achieved. A testament to what is possible when the people of Iraq work together."

Hundreds of British troops are based in Maysan province and are not expected to withdraw from the area immediately, although Britain plans to scale back its presence in Iraq by about 1,600 troops in the next few months.