Belgium's Coordinating Body for Threat Analysis (OCAM) has increased the risk level at big sporting and cultural events from level Two (medium) to level Three (serious), in the wake of the deadly terrorist attacks in neighboring France.

Belgian Prime Minister Charles Michel announced the increase late night Saturday, after a meeting with the country's national security council, which held its second meeting this weekend following the Paris attacks on Friday evening.

According to Michel, OCAM's decision means the Belgian army could be deployed at events that attract a large number of people.

Since Saturday morning, the Belgian government has been pondering whether to increase the security risk level in the country, including raising the vigilance level for public gatherings, airports, railway stations and roadside checkpoints.

The government has instructed all local police forces to carry out systematic searches at entries to public events, stating that local forces had a vital role to play in gathering and passing on intelligence.

French and Belgian police have been carrying out random roadside checks on vehicles, which led to long traffic jams at some border crossings.

The Belgian federal prosecutor announced Saturday that four arrests had been made in Molenbeek, one of the 19 municipalities surrounding the Belgian capital of Brussels, following the terrorist attacks in Paris in which 129 people were killed and 352 were injured.

One of the people arrested was in Paris on Friday night, Michel told local television.

According to French media, investigators are trying to find the assailants who allegedly have fled to Belgium from the scene of the Paris massacre.

During a press conference, the Belgian public prosecutor confirmed it had received four requests for help from the Paris prosecutor in connection with the deadly attacks.

A grey Volkswagen Polo car registered in Belgium was found near the Bataclan theater on Boulevard Voltaire in the 10th arrondissement of Paris.

The Belgian federal prosecutor has opened a case related to crimes of organizing a terrorist attack and participating in the activities of a terrorist group.