"One Iraqi was killed and (another) was hit in the neck ... He will probably die," said a US soldier at the scene of the 9:00 am (0600 GMT) attack in the capital's Karrada district.

Private Matthew Andersen said an Iraqi translator with the US soldiers was also hurt when the bomb hit the convoy of four vehicles.

A separate US military spokesman said a third Iraqi was hurt but there were no American casualties.

Roadside bombs against US convoys and patrols are common in and around Baghdad.

Iraqi police said Tuesday they had reinforced security in the capital in anticipation of more insurgent attacks over the New Year.

"Police have taken strict security measures with the approach of the New Year and have put in place plans to confront possible terrorist attacks against Iraqis and foreigners," Baghdad police chief General Hassan Ali Ubeidi told AFP.

More than 11,000 officers have been deployed, he said.

"Police are going to step up patrols, set up checkpoints and intensify operations across the city," Ubeidi said.

On Christmas Day a roadside bomb blew off the hand of a policeman trying to defuse it, and wounded at least one civilian. Last Thursday's bombing occurred as rebel rockets and mortars pounded the city with attacks on a major hotel and three foreign embassies.

But there were no deaths and few injuries in what the US-led coalition that administers Iraq called a "weak and ineffective" action.