Antwerp police intercepted a van containing seven heavily armed men on the IJzerlaan on Tuesday evening, they confirmed after Gazet van Antwerpen published the information.
An investigation is underway to determine what the group was up to and had links to a major cocaine seizure that took place earlier in the day in the port of Antwerp.
"I can confirm that our arrest unit carried out a high-risk operation yesterday evening with the support of dispatching, the Realtime intelligence centre (RTIC), emergency aid and a High Risk Protection unit, among others", said Antwerp police spokesman Wouter Bruyns, who declined to comment further. The public prosecutor's office was not immediately able to provide any further information.
On Tuesday, "several tonnes" of cocaine were seized in the port of Antwerp. The drugs were concealed in a cargo of soya flour, according to the Federal Public Service Finance. So far authorities suspect that the gunmen were trying to recover the cargo.