The attack came as visiting U.S. Defense Secretary Robert Gates planned to meet with President Hamid Karzai and other Afghan officials in the capital, Kabul .
Gates was "nowhere near the blast," said a U.S. Embassy official who spoke on condition of anonymity because she was not authorized to speak on the issue publicly.
The bomber struck a two-vehicle convoy belonging to NATO's International Security Assistance Force near the city's airport, Interior Ministry spokesman Zemeri Bashary said.
Twenty-two civilians were wounded in the attack, NATO said in a statement.
There were no casualties in the NATO convoy, said Lt. Col. Thomas Dillschneider, an ISAF spokesman.
The attacker's car was completely destroyed and three private vehicles, including a minibus, were damaged, said an Associated Press reporter at the scene.
Ten people who were riding in the minibus near the blast were among those wounded, said Ghulam Rasool, a police officer.
Militants have launched more than 130 suicide attacks this year - a record number. At least 6,200 people have died in insurgency-related violence in 2007, also a record, according to an Associated Press tally of figures from Afghan and Western officials.
Suicide attacks frequently target international and Afghan security forces, but most of the casualties are civilian passers-by.
On Monday, another suicide bomber blew himself up next to a police patrol in southwestern Nimroz province, killing two police officers and two civilians, said provincial Governor Ghulam Dastagir.
The blast also wounded three officers and four civilians, Dastagir said.
Putin said that NATO increased its military personnel by 10,000 people in the areas where NATO troops should not even be in accordance with key documents
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969