The two dignitaries were arriving in the Afghan capital to attend an International Conference on Afghanistan and the attack was confirmed by the Swedish Foreign Minister on his blog.
"... rockets hit the airport just when we were coming in to land," read the blog posted at 05:30 hrs in the morning (local time).
Officials later confirmed that the flight was diverted to nearby Bagram base from where the two VVIPs were ferried by a Black Hawk helicopter.
"... together we spent a few hours on the giant US Bagram base just north until the situation would become clearer and arranged transportation to Kabul. There were two US Black Hawk, which then took us away," Bildt wrote.
He said, "the Taliban and others would try to disrupt the important conference here was obviously to be reckoned with... Our presence here is a demonstration of our support for peace and stabilisation process in the country".
Ban was to inaugurate the biggest ever international conference being held in the Afghan capital in which 70 world leaders, including External Affairs Minister S M Krishna and US Secretary of State Hillary Clinton, are attending.
The conference is aimed at discussing a major plan to hand over the security and military affairs to the Afghan government in all the 34 provinces by 2014.