“Numerous elements in the investigation [of the attacks on Brussels airport and subway] have shown that the terrorist group originally intended to strike in France again,” the Belgian federal prosecutor’s office announced on Sunday. “Eventually, surprised by the speed of the progress in the ongoing investigation, they urgently took the decision to strike in Brussels,” the statement said.

Investigators have uncovered an increasing number of links between the group of attackers who targeted Paris and its surrounding area on Nov. 13, killing 130 people, and the group that bombed the Brussels airport and Maelbeek metro station on March 22, killing 32.