The terror cell which carried out the Brussels bombings last month had been planning to launch a new attack on Paris, the Belgian prosecutor has said.
Those who launched the 22 March attacks which killed 32 people decided to rush their plans and target Brussels instead, prosecutors claimed.
The terror cell was "surprised by the speed of the progress in the ongoing investigation", the office said.
Investigators have said there are close links between the perpetrators and the Isis terror cell which killed 130 people in Paris on 13 November.
The Brussels attacks involved two suicide bombers at Zaventem Airport and another at Brussels' Maelbeek metro station the same morning.
Four other men have been charged by Belgian authorities with participating in "terrorist murders" and the "activities of a terrorist group" in connectection to the attacks.
They include Mohamed Abrini, who prosecutors have identified as the so-called "man in the hat" who was seen walking alongside the two airport bombers.
The other three suspects have been identified as Herve B M and Bilal E M and Osama Krayem, a Swede known to have travelled to fight in Syria.
Additional reporting
