The blast occurred at Hamid Karzai International Airport a day after Pakistan's army chief visited the Afghan capital in an effort to revive peace talks.
The blast took place after a vehicle packed with explosives was detonated by a suicide bomber.
Pakistan -- the Taliban's historic backers -- hosted a milestone first round of talks in July but the negotiations stalled when the insurgents belatedly confirmed the death of longtime leader Mullah Omar.
Afghan forces are currently battling to push out Taliban insurgents who seized large swathes of the key opium-rich district of Sangin in southern Helmand province. Observers say the intensifying insurgency highlights a push by the militants to seize more territory in a bid to wrangle greater concessions during talks.
OneIndia News (With agency inputs)