BRUSSELS — Belgium’s customs officers arrested 40 people Wednesday and seized tens of millions of counterfeit cigarettes in raids targeting 10 illegal production sites across the country.

Belgium’s Finance Ministry described the operation as the biggest in the history of the customs service.

In addition to the cigarettes falsely branded as Marlboro, Richmond, Prince and Regina, customs officers also discovered tons of tobacco, cigarette filters, empty packs and glue.

Authorities said illegal production of manufactured tobacco has been growing in the European Union, with cigarettes seized in Belgium mainly destined for Britain and France, where excise duties are higher.