Paris attack suspect Salah Abdeslam refuses to speak when asked about Tuesday's attacks in Brussels, Belgian prosecutors say.
Abdeslam, arrested last week in Brussels and initially cooperative, had "exercised his right to silence" and said nothing when interviewed after Tuesday's bombings according to prosecutors in Brussels.
He was seized days before the Brussels attacks, in which 31 people died.
Meanwhile Belgian officials named the second suicide bomber in Tuesday's attack at Brussels airport as Najim Zaachraoui, and said that his DNA was found at sites of the November Paris attacks.
Brahim el-Bakraoui had already been named as one of the perpetrators of the airport attack, which left 11 people dead. A third remained unidentified.
Thirty-one people died in bombings at Brussels airport and a metro station.
So-called Islamic State (IS) claimed to have carried out both the Brussels and Paris attacks.
Twelve arrests after Brussels attacks
The news came as three people were arrested in the Forest, Saint-Gilles and Schaerbeek areas of Brussels in connection with the attacks.
In the most recent raid, a man carrying a backpack was shot in Schaerbeek district after refusing to obey police orders, media say. Controlled explosions were carried out.
An area near Meiser square was sealed off by heavily armed police and military vehicles.
The operation has now finished and the cordon has been lifted.
Schaerbeek mayor Bernard Clerfayt said a man had been arrested and shot in the leg.
Prosecutors said the arrests were linked to a raid in Paris on Thursday, where an attack was apparently foiled.
Six had already been detained in the Schaerbeek and Jette districts, and in the city centre on Thursday.
Reda Kriket, 34, was arrested in Paris' north-western Argenteuil suburb, alleged to be in the "advanced stage" of plotting an attack.
Two suspected jihadists were also detained in Dusseldorf and Giessen in Germany on Wednesday and Thursday - both with suspected links to one of the Brussels bombers according to Der Spiegel reports
One of those arrested in Germany had suspicious text messages on his mobile phone referencing Brussels.
'Je suis Bruxellois'
US Secretary of State John Kerry, visiting Brussels, said that IS would be destroyed.
Standing alongside Belgian Prime Minister Charles Michel, he expressed his condolences and solidarity with Belgium, declaring "Je suis Bruxellois".
The Western alliance would continue its fight to destroy IS, Mr Kerry said.
"We will not be intimidated. We will not be deterred."
The Brussels bombings continued to have political repercussions, with questions surrounding the issue of whether more could have been done to prevent them.
Turkey has said it arrested and deported one of the bombers, Brahim el-Bakraoui, last June, warning Belgium he was a "foreign fighter" - but the message was "ignored".
The Belgian interior and justice ministers said they had offered their resignations but the prime minister refused to accept them.
Bakraoui's brother, Khalid, struck at Maelbeek metro station, where 20 people died.