Jacques Monsieur, 66, was held at a large farmhouse near the Portuguese town of Evora on Wednesday evening, Belgian federal police said in a statement.

The Brussels appeals court sentenced him to four years in jail and a fine of 1.2 million euros ($1.33 million) in October 2018 for illegal arms trafficking and participation in a criminal organisation.

Monsieur was sentenced to 23 months in prison in the US in 2010 for trying to smuggle fighter jet parts to Iraq.

In 2002, a Brussels court sentenced Monsieur to more than three months behind bars for selling weapons including grenade launchers and missile parts to Iran, China, Ecuador, Bosnia-Hercegovina and Croatia in the 1980s and 1990s.

His latest arrest came partly as a result of his enthusiasm for horses -- an unpaid 2,500-euro bill for transporting horses to Portugal put investigators on Monsieur's trail.