WASHINGTON (REUTERS) - Two brothers who carried out suicide bombings in Brussels this week were known to US government agencies before the attacks, according to two sources familiar with the matter.

The sources said that Khalid El Bakraoui and Brahim El Bakraoui were both on US government counterterrorism watch lists before the March 18 arrest of Salah Abdeslam, a French national whom prosecutors accuse of a key role in the Nov 13 Paris attacks.

Belgian prosecutors have identified Brahim El Bakraoui as one of two suicide bombers who attacked Brussels' Zaventem Airport, while they say Khalid El Bakraoui was the man who carried out a suicide bombing at Brussels' Maelbeek Metro station, near European Union headquarters.

(This is a developing story)