A suicide car bomber struck near a military base at the international airport in Kabul early Tuesday. Three civilians were killed and six were wounded.
The Taliban claimed responsibility for the blast, which also wounded an international soldier.
The airport is used by civilians as well as foreign troops operating in the country. The bombing took place outside the gate on the military side.
Taliban insurgents targeted the airport with rocket attacks last month, as they intensified their campaign of violence ahead of the country's presidential election, Voice of America reports.
News agencies also reported a Toyota 4x4 blew up trying to target a convoy of international soldiers Afghan officials said, but killed a passing cyclist and pedestrian.
Thick black smoke billowed from the twisted remains of the vehicle following the blast at around 8.15am (4.45 BST) close to the main military entrance at Kabul International Airport. A badly damaged saloon car could be seen nearby.
Three Americans and a Belgian were wounded in the attack as well as six Afghan civilians.
The road to the airport is a regular route for international workers and troops and a common target for suicide bombers Zabihullah Mujahid, a spokesman for the Taliban, claimed responsibility for the blast, and said the target had been foreign soldiers at the airport, Telegraph.co.uk reports.
The New York Times quoted a witness at the scene as saying, “I saw two American soldiers lying on the ground in blood,” along with six injured Afghan civilians.
NATO officials had no immediate comment.
Three weeks ago, Mr. Mujahid claimed responsibility for a similar attack outside NATO headquarters in Kabul. At the time, he warned that the Taliban would “continue this kind of operation in the future and we will accelerate our operations against the Afghan and foreign forces.”
On Aug. 15, less than a week before Afghanistan’s national elections, a suicide car bomber struck just outside the NATO headquarters and the Ministry of Transportation, a block from the United States Embassy in Kabul.
The blast killed seven people — all civilians — and wounded 91. It was the first major attack in the capital since February, when suicide bombers mounted an assault on the Justice Ministry, killing 20 people, The New York Times reports.