Update 3 | Third Brussels attacks suspect still on the run - prosecutor

Reports by Belgian media that a key suspect in the attacks in Brussels had been arrested, have been denied by the Belgian prosecutor.

Federal prosecutor Frederic van Leeuw has confirmed that Najim Laachraoui is still at large.

A Belgian newspaper and television station said judicial sources had informed them of the arrest. They claimed that Laachraoui, thought to be the man seen in a CCTV image taken before the Zaventem airport attack, was reportedly held in the Anderlecht area.

Two of the other attackers have been named in Belgian media as the brothers Khalid and Brahim el-Bakraoui.

Meanwhile, according to AP, authorities have officially identified two brothers as suicide bombers on the Brussels metro and airport. Van Leeuw said that Khalid al-Bakraoui has been identified as the metro's suicide bomber.

Police have also found a will belonging to one of the suicide bombers on his computer.

Twin explosions at the airport and another at a metro station on Tuesday left 31 dead and 270 wounded. Two victims have been identified and have been named as student Leopold Hecht, 20, and Adelma Tapia Ruiz, a mother of two.