Brussels, Nov 21 (EFE).– Belgium’s capital was effectively placed on lockdown on Saturday – with metro lines, shopping malls and museums shuttered and concerts and other events canceled – after authorities raised their terror alert to the highest level due to the risk of “imminent” attacks.

The country’s crisis center announced early Saturday that the terror alert level had been raised one notch to level four, an exceptional measure that had been adopted only twice before and which took Brussels’ residents by surprise.

Belgian Prime Minister Charles Michel said the decision was based on intelligence indicating the risk of an attack by “several people with arms and explosives, perhaps in different places.”

The information warned of a potential “Paris-style attack” targeting public transportation or streets and shopping malls, as well as large events attracting big crowds of people, Michel said.

“We’re going to mobilize large-scale security capacities,” the prime minister said.

Museums, concert halls, sporting arenas and other public places in Brussels have been shuttered and will remain closed throughout the weekend.

Elsewhere in Belgium, the terror alert remained at level 3, which indicates that attacks are “possible or probable.”

That level was established nationwide last week after investigators discovered links between Belgium and the Nov. 13 terrorist attacks in Paris that left at least 130 dead. EFE