Two powerful bombs exploded just outside Baghdad's tightly-guarded Green Zone on Tuesday as US Deputy Secretary of State John Negroponte was due to address reporters inside, an AFP correspondent reported.

An Iraqi military officer said at least one soldier was wounded in the blasts that went off in quick succession.

The first blast targeted a parked Iraqi armoured vehicle and a car bomb went off minutes later at a nearby parking lot opposite the foreign ministry, on the edge of the Green Zone where Iraq's government and the US embassy are located.

Witnesses said a limpet-type magnetic mine had been used in the first attack against the armoured vehicle parked at a security checkpoint leading to the Green Zone.

Several cars were also damaged and Iraqi firefighters put out the flames before they could spread to other cars.

Minutes after the attacks, Negroponte began his scheduled press conference with Iraqi Foreign Minister Hoshyar Zebari.

Outside the Green Zone, soldiers fired in the air to keep motorists and pedestrians out of the bombed area.

The attacks in the central Salhiyah neighbourhood of Baghdad came despite a tight security cordon and stepped-up checks on vehicles and followed a spate of bombings in the Iraqi capital last week.

The US military claimed on Saturday it had killed an al-Qaeda militant who planned some of the biggest bombings in Baghdad and who killed a group of Russian diplomats in 2006.

Mahir Ahmad Mahmud al-Zubaydi, also known as Abu Assad or Abu Rami, was killed along with an unidentified woman in Baghdad's Sunni district of Adhamiyah on Friday, the US military said.

The killing has dealt a severe blow to al-Qaeda in Baghdad, the US military said last week.

Abu Rami was reportedly also responsible for multiple car bombings and mortar attacks in Sadr City in 2006 and 2007, including car bombings in November 2006 that killed more than 200 people.