Belgian police have made 21 arrests in anti-terror raids, but suspected Paris attacks gunman Salah Abdeslam remains at large, the authorities have said.

Some 22 raids were carried out Sunday across Brussels and Charleroi, the federal prosecutor"s spokesman said.

Brussels remains on the highest level of terror alert. Universities, schools and the metro system will stay closed on Monday.

More than 130 died and 350 were injured in the Paris attacks 10 days ago.

Police fired two shots at a car during an operation in the Brussels district of Molenbeek, injuring one suspect who was later arrested.

No weapons or explosives were found during the searches on Sunday, spokesman Eric Van Der Sypt told a news conference.

"On Sunday 22 November the Belgian authorities announced that the decision taken the previous day to increase the security threat level for the Brussels region from 3 to 4 will remain in effect. The situation will be assessed again during the course of tomorrow afternoon (23 November).As a consequence, the General Secretariat of the Council (GSC) has decided to raise its alert state to ORANGE (from yellow). This is a precautionary measure, consistent with the increased Belgian threat level.

This higher alert state means that a number of security measures will be introduced in addition to those already put in place as from 16 November in the light of the increased threat following the Paris terrorist attacks.

As a result of the increase in alert state, the Presidency of the Council, in consultation with the GSC, has decided to cancel the majority of non-essential meetings scheduled to take place tomorrow in the Council building. However the EYCS Council, the Eurogroup, and a limited number of senior officials meetings will take place as planned.

The Secretary General has been in contact with GSC staff about the implications of the higher alert state for their working arrangements and travel to and from their place of work.

We remain in constant contact with the Belgian authorities, the member states and our counterparts in the other EU institutions. We are ready to make any further adaptations to our security measures should that prove necessary., "- said the European Commission"s press secretary Margarita Shinas.