BAGHDAD - A suicide attacker detonated a car bomb near the UN headquarters in Baghdad on Monday, killing himself and a security guard, a month after a huge truck bomb at the building killed more than 20 people.

"This is a suicide bomb," Captain Sean Kirley, a U.S. officer at the scene, told Reuters. He said more than eight people had been wounded in the blast.

The explosion came on the eve of the annual United Nations General Assembly in New York, which an Iraqi delegation had been due to attend. One of those due to represent Iraq at the assembly, Iraqi Governing Council member Akila al-Hashemi, was critically wounded on Saturday in an attack in Baghdad.

Kirley said the blast happened at about 8:10 a.m. (0410 GMT), 250 metres (yards) from the United Nations headquarters, and destroyed at least six other vehicles.

He said the car bomber drove into the UN car park and was stopped by an Iraqi security guard before reaching the parking lot's main checkpoint.

"The driver and the guard engaged in conversation and the bomb was detonated from inside the vehicle," Kirley said. "The damage to the other cars was catastrophic," he added.

U.S. forces were helping Iraqi personnel guard the headquarters at the time, but there were no American casualties, Kirley said. SEVERAL WOUNDED

At a nearby hospital, Wahid Karim said he had been in a car driving past the UN building when the bomb went off. "I didn't even hear it. I lost consciousness," he said. "I came round in the car. The driver was bleeding."

He said doctors had removed a piece of metal from his head.

Following last month's truck bomb attack on the building, many UN staff have been working in makeshift tents and cabins around the site.

Washington has said last month's bombing was probably the work of loyalists of ousted Iraqi president Saddam Hussein or militants linked to Osama bin Laden's al Qaeda network.

The rising death toll in Iraq is putting more pressure on President George Bush at home as he seeks a new UN resolution to create a multinational force for the country.

But France and Germany, opponents of the U.S.-led war that toppled Saddam, are demanding that the United States agree to a fast handover of power to Iraqis. The United States believes a speedy power transfer would lead to failure.

Bush, who is to address the UN General Assembly on Tuesday, said he did not consider it essential to grant the United Nations a larger political role to obtain a new resolution backing the multinational occupation force.

"I'm not so sure we have to, for starters," he said.