Both the Federal Police and Federal Prosecutor's Office said the "threat was taken seriously," but "nothing was found" during a security sweep of the Brussels metro as a precaution, according to the euronews.com service.
It said the European Commission received two threatening emails, warning of an "explosion" on the city's metro.
Meanwhile, the US embassy in Belgium released a security alert warning of a "threat of a possible metro attack to be conducted today, March 8."
It urged people to "use caution when traveling in and around Brussels and avoid crowds."
Belgian daily Le Soir said the European Commission notified the police on Tuesday afternoon of an email written in Russian and referring to an attack planned for Wednesday, the Reuters news agency reported.
A statement from the European Parliament to MEPs said that it was "monitoring the situation closely," alongside the national authorities, according to euronews.com.
An investigation was ongoing to find those responsible, it reported.
(gs)
Source: PAP, Reuters, euronews.com, be.usembassy.gov