A suicide car bomber has struck at the gates of Jalalabad airport in eastern Afghanistan, officials said, killing nine people in an attack insurgents said was revenge for US troops burning Korans.

The explosion comes after six days of deadly protests in Afghanistan over the disposal of Korans and other Islamic texts in a burn pit last week at a US military base north of the capital.

American officials have called the incident a mistake and issued a series of apologies.

Afghan president Hamid Karzai has urged calm, saying that Afghans should not let the insurgents capitalise on their indignation to spark violence. The latest attack appeared to be a sign that the Taliban are seizing the opportunity to do just that.

The bomber drove up to the gates of the airport - which serves both civilian and international military aircraft - shortly after dawn and detonated his explosives in a "very strong" blast, said Nangarhar provincial police spokesman Hazrad Mohammad.

Among the dead were six civilians, two airport guards and one soldier, Mr Mohammad said. Another six people were wounded, he said. An Associated Press photographer saw at least four destroyed cars at the gates of the airport.

Nato forces spokesman Captain Justin Brockhoff said that no international forces were killed in the attack and that the installation was not breached by the blast.

The Taliban claimed responsibility for the attack, saying a suicide car bomber had driven up to the airport gate and detonated his explosives as international forces were changing from night to morning guard duty. "This attack is revenge against those soldiers who burned our Koran," Taliban spokesman Zabiullah Mujahid said in an email.

More than 30 people have been killed in protests and related attacks since the incident came to light last Tuesday, including four US soldiers. On Sunday, demonstrators hurled grenades at a small US base in northern Afghanistan and the ensuing gun battle left two Afghans dead and seven Nato troops injured.

However, the top US diplomat in Afghanistan said yesterday that the violence would not change Washington's course. "Tensions are running very high here, and I think we need to let things calm down, return to a more normal atmosphere, and then get on with business," Ambassador Ryan Crocker told CNN.