A second senior US official made a surprise visit to Iraq Wednesday as Washington sought to play up Iraq's political transition, but violence shadowed the trip as nine were killed in a bomb blast.

Deputy Secretary of State Robert Zoellick arrived less than a day after US Defence Secretary Donald Rumsfeld made an unannounced visit.

Yesterday, a US Defence Department convoy in an attack that killed five Iraqis and injured four US contract workers, the US military said.

Shortly after Zoellick's arrival, a bomb blew up near the oil city of Kirkuk as a group of Iraqi guards was trying to defuse it, killing 12 and wounding four, the local police chief said.

And in Baghdad there was a series of explosions, including a bomb that struck an oil tanker, sending thick clouds of black smoke pouring into the air over the east of the capital.

Another bomb detonated on the road to the airport, wounding seven Iraqis.

The attacks again underscored the intense security challenges facing Iraq's newly elected leaders, who are still deliberating over the formation of a government more than two months after an election in late January.

"We are obviously, in the aftermath of this election, in a key period of political formation," Zoellick told reporters earlier on his military aircraft.

"This is a process of political transition, the formation of Iraqi democracy," he said. Shortly after his arrival in Baghdad, Zoellick travelled to Falluja, west of the capital and the site of some of the worst unrest in Iraq over the past two years.

In Falluja, Zoellick discussed reconstruction with US troops who are helping rebuild the city after a mass US offensive there last November which left much of it in ruins.

Zoellick, Secretary of State Condoleezza Rice's top deputy, was to return to Baghdad later in the day to meet President Jalal Talabani and Prime Minister Ibrahim Jaafari, as well as other officials.
 
Of the four blasts that struck Baghdad, one was a car bomb targeting a joint US-Iraqi military convoy in the Amiriya district of western Baghdad, seriously wounding four civilians, witnesses and hospital officials said.

Three other explosions struck convoys in other parts of the city, including an attack on a US convoy near the airport.

The US military hopes to cut troop numbers in Iraq next year but that will depend on the training of Iraqi security forces, which have lost hundreds in bombings and attacks.

Iraqi troops have made progress against the insurgency since the election, and violence appears to have eased since then, but millions of Iraqis who defied suicide bombings to vote want to see the new government do more to end the bloodshed.

As well as tackling the insurgency, they will also have to confront rampant crime and an economy that is largely in ruins. Crime is of particular concern, with gangs responsible for hundreds of violent kidnappings over the past year.

After a lull in abductions, a US contractor was kidnapped from a reconstruction site near Baghdad on Monday. More than 150 foreigners and thousands of Iraqis have been abducted in the last year and many of them have been killed.
 
On his visit, Rumsfeld warned corruption and purges of security forces and ministries could sap the credibility of Iraq's new leaders and undermine the battle against insurgents.

Also yesterday, Al-Jazeera television aired a video that it said showed an American kidnapped two days earlier in the Baghdad area pleading for his life.

(China Daily April 14, 2005)