Brussels attack: Terror suspects identified as brothers Khalid and Brahim El Bakraoui

Belgian state broadcaster RTBF has identified two of the attackers who targeted Brussels as brothers Khalid and Brahim Bakraoui.

The report issued on Wednesday says the brothers were known to police for past crimes, but nothing relating to terrorism.

REBF says Khalid El Bakraoui had rented an apartment raided by police last week in an operation that led authorities to top Paris attacks suspect Salah Abdeslam

According to Reuters, the attacker still at large is Najim Laachraoui, 25, a man already sought by the police since Monday, Belgian newspaper DH said.

Laachraoui's DNA has been found in houses used by the Paris attackers last year, prosecutors said on Monday, and he had traveled to Hungary in September with Paris attacks prime suspect Salah Abdeslam.

The blasts on Tuesday claimed by the Syrian-based militants four days after the arrest in Brussels of a prime suspect in November's Paris attacks, sent shockwaves across Europe and around the world, with authorities racing to review security at airports and transit systems, and drawing an outpouring of solidarity.

Security experts believed the blasts, which killed about 20 on a metro train running through the area that houses European Union institutions, were probably in preparation before Friday's arrest of locally based French national Salah Abdeslam, 26, whom prosecutors accuse of a key role in the Nov. 13 Paris attacks.

Islamic State said in a statement that "caliphate soldiers, strapped with suicide vests and carrying explosive devices and machineguns" struck Zaventem airport and Maelbeek metro station.

(People hold a banner reading in French and Flamish "I AM BRUSSELS" as they gather around floral tributes, candles, belgian flags and notes in front of the Bourse of Brussels on March 22, 2016 in tribute to the victims of Brussels It was not clear, however, that the attackers used vests.) - AFP

The suspects were photographed pushing bags on trolleys, and witnesses said many of the airport dead and wounded were hit mostly in the legs, possibly indicating blasts at floor level.

(With Reuters/PTI inputs)