Broadcaster RTBF reported the brothers were known to police for organized crime, not acts of terrorism.
One of the brothers, Khalid, had rented an apartment in the Brussels suburb of Forest, which the police raided last week. The shootout at Khalid's apartment led to the killing of one suspected terrorist and the following capture of Paris attacks suspect Saleh Abdeslam, according to RTBF.
At least 34 people were killed and more than 100 others were injured in multiple explosions at Zaventem airport and a metro station in Brussels on Tuesday morning, Belgian public broadcaster VRT reported.
The first two blasts were reported at Zaventem airport, where at least 14 people were killed and dozens injured at around 8 a.m. local time (0700GMT), according to VRT.
Just over an hour later, an explosion hit Maelbeek metro station during the late rush hour, located near several EU offices, killing 20 people according to VRT.
A news agency linked to Daesh said the group had claimed responsibility for the attack.
An image of three suspects at the airport was released to the media. The men were pictured in CCTV footage pushing luggage carts. Brussels police issued a wanted notice for one of the men seen pushing a luggage trolley through the airport. The other two are the el-Bakraoui brothers.
As the terror alert in Brussels was raised to the highest level, the federal prosecutor called for the media not to share information that could jeopardize the investigation. Le Soir newspaper said it would abide by the request.
Metro stations were closed and flights to Zaventem airport diverted while the Eurostar rail service was also cancelled into and out of Brussels.
Schools, shopping centers, cinemas and theaters were also closed.
Zaventem airport’s Chief Executive Arnaud Feist said the airport would be closed Wednesday.
A three-day period of mourning was declared by Interior Minister Jan Jambon and residents were advised to restrict their movements. "For now, we ask the population to prevent movement," Prime Minister Charles Michel tweeted.
He later condemned the attacks via Twitter. "I strongly condemn these hateful attacks. Our thoughts go out to the victims and their families. We stand united against terrorism."
A Turkish man was among those injured at the airport, Ali Baris Ulusoy, Turkey’s consul general to Brussels, said.
The man, who works as a cleaner at the airport, is not in a critical condition, he said.
The attacks came four days after a counter-terrorism raid in Brussels led to the capture of Saleh Abdeslam, the prime remaining suspect in November’s Paris attacks that killed 130.