"A suicide bomber had driven a vehicle into the first checkpoint on the road into the airport," said Kabul police chief Sayed Gul Agha Rouhani, reported BBC.
Taliban has claimed responsibility for the attack. Afghanistan has witnessed a rise in terror attacks since announcement of death Taliban leader Mullah Omar.
According to reports, casualties are expected in the attack which appeared to target a convoy of armoured cars, according to security officials at the scene.
This is the latest in a series of deadly attacks in Kabul in the past few days.
At least 35 people were killed and hundreds more were wounded in attacks on Friday near a police academy.
In the early hours of Friday, a truck carrying explosives was detonated near an army base in the Shah Shahid area, claiming 15 lives.
High alert was already sounded in Kabul after last week's attacks which killed at least 50 civilians and security forces personnel in the worst violence seen in the city in years.