Brussels enters its fourth day on lockdown

Brussels has entered its fourth day on high terror alert, as security measures continue to disrupt normal life in the Belgian capital.

Schools are set to reopen on Wednesday as well as parts of the subway system which have been shut in recent days, but the city will remain at the highest level of alert for at least another week, the country's prime minister Charles Michel said.

"We are very alert and call for caution," Mr Michel said.

On Monday an explosive vest similar to those used in the November 13 attacks in Paris during which 130 people died was discovered in the suburb of Chatillon-Montrouge by a street cleaner.

The suicide vest was made up of the same types of explosives used to cause carnage in the French capital earlier this month, a police official said.