The Taliban claimed responsibility and called the attack "retaliation" for the burning of the Korans.
A suicide car bomber killed nine people in an attack on a military airport in eastern Afghanistan on Monday, officials said, the latest bloodshed since copies of the Koran were burned at a NATO base last week.
There was no official indication the explosion at the gates of Jalalabad airport was linked to the deadly protests, but the Taliban claimed responsibility for the attack as "revenge" for the Koran burnings.
Nineteen Afghan civilians and law enforcement officers and four NATO soldiers were wounded in the blast, a spokesman for the NATO-led International Security Assistance Force (ISAF) in Nangarhar province, of which Jalalabad is the capital, said.
Jalalabad airport is almost exclusively used by NATO and the U.S. military.
Anti-Western fury has deepened significantly since the desecration of the Muslim holy book at the main NATO Bagram air base in Afghanistan. NATO described the incident as a tragic blunder.
The U.S. Embassy warned of a "heightened" threat to American citizens in Afghanistan and many Westerners are on "lock down", meaning they are not allowed out of their fortified compounds.
Riots have raged across Afghanistan over the past week despite widespread apologies from U.S. leaders, including President Barack Obama and military commanders.
Seven U.S. military trainers were wounded on Sunday when a grenade was thrown at their base in Afghanistan's north.
Chants of "Death to America!" have come to characterize the protests and some demonstrators have hoisted the white Taliban flag.
Karzai simply isn't doing enough to bring the situation under control. Where's a curfew? How about martial law in some areas? Why not try to defuse the crisis rather than allow the protests to grow and become more violent?
The truth is, the riots are helping Karzai. He is being identified as on the side of the rioters and against America. Anything he can do to show his independence from NATO is a plus for him and he is going to ride the wave of anti-Americanism as far as it can take him.
And then he will expect American soldiers to continue to fight and die for his regime.