Police in Belgium started a huge operation targeting drug traffickers on Tuesday involving more than 1,200 officers.
Searches were carried out from 5am, centred in the province of Antwerp, home to one of Europe’s biggest ports. Broadcaster RTBF said the focus was a drug smuggling network with international connections.
The Belgian port city is one of Europe’s main ports of entry for cocaine, with thousands of containers reaching Antwerp every day.
Trafficking in the city has led to a surge of violence with frequent gun battles and grenade attacks.
A suspected drug trafficker was arrested in Dubai last year over claims that he was linked to the violent turf wars. He was later released by police.
The operation on Tuesday came after authorities in Belgium and three other countries last year dismantled a criminal drug trafficking network that shipped cocaine worth hundreds of millions of dollars into Western Europe.
The investigation, which began when a container with 2.8 tons of cocaine was found last year in Antwerp, uncovered an international network with connections in at least four European countries and South America.
European police forces have arrested hundreds of top-tier criminals after police cracked an encrypted messaging service used to organise major drug smuggling operations and gangland hits.
French and Dutch police said in July that they were harvesting data from the criminals' EncroChat service.