Armed police launched a major new raid in Brussels in the wake of the suicide attacks, in the Schaerbeek area of the capital, Belgian media reported Friday, a day after six suspects were arrested over the carnage.
An explosion was heard at the start of the operation, Belga news agency reported, while the RTBF broadcaster said a man had been "neutralised", but there was no immediate confirmation by officials.
Bomb disposal experts were also on site, reports said.
Police had sealed off the area, an AFP reporter at the scene said.
The site of the raid is in the same district from where three airport attackers left on Tuesday morning carrying suitcase bombs, although only two went off.
During a series of raids in Schaerbeek on Tuesday night police found 15 kilos of high explosive, bomb-making chemicals and an Islamic State group flag.
