BRUSSELS — Belgian authorities were searching Wednesday for a top suspect in the country’s deadliest attacks in decades, as the European Union’s capital awoke under guard and with limited public transport after 34 were killed in bombings on the Brussels airport and a subway station.

Police conducted raids into the night and circulated a photo of three men seen in the airport suspected of involvement in Tuesday’s attacks.

Belgian state broadcaster RTBF has identified two of the attackers as brothers Khalid and Brahim El Bakraoui. They are believed to have blown themselves up in the attacks.

The third man is at large and has not been identified.

The report Wednesday says the brothers were known to police for past crimes, but nothing relating to terrorism. RTBF says Khalid El Bakraoui had rented an apartment which was raided by police last week in an operation that led authorities to top Paris attacks suspect Salah Abdeslam.

Last week, Belgian police said they were hunting for a suspected Abdeslam accomplice, Najim Laachraoui. He is believed to have made the suicide vests used in the November attacks in Paris, in which 130 people were killed, according to a French police official who said Laachraoui’s DNA was found on all of them and in a Brussels apartment where they were made.

The official spoke on condition of anonymity because the investigation is continuing.

The airport and several Brussels metro stations remain closed Wednesday. Security forces stood guard around the neighborhood housing headquarters of EU institutions, as nervous Brussels residents began returning to school and work under a misty rain.

The Islamic State group claimed responsibility for the attacks.