Jose Alberto Azeredo Lopes, who served as defence minister from November 2015 until October 2018, is under investigation for alleged denial of justice, favouritism and abuse of power, according to the prosecutors' summary of the indictments.

Senior figures in the military and police forces have also been arrested over the theft of rockets, grenades, and cartridges at the end of June 2017.

In all, there will be 23 defendants, including the nine alleged perpetrators who face charges of arms and narcotics trafficking, organised crime and terrorism.

Politically weakened by the scandal, Azeredo Lopes resigned from the Socialist government last October, but categorically denied he had been informed of any cover-up operation.

At the end of June 2017, thieves broke into a military arms depot in Tancos, central Portugal, where security cameras had been out of order for two years.

They got away with 44 anti-tank rockets, 150 hand grenades, 18 tear gas grenades, and 1,450 nine-millimetre cartridges worth an estimated 35,000 euros.