"Some prime suspects remain at large," said Carabinieri paramilitary police commander, Francesco Iacono, commenting on initial news reports in Italy and in Germany that up to 11 suspects had been apprehended.

The suspects were picked up in morning raids, involving 150 Carabinieri, in the southern town of San Luca -- the traditional stronghold of the 'Ndrangheta, the Calabrian version of the mafia -- as well as in the nearby Locride area and in the northern cities of Udine and Bologna.

Two women, Maria Pelle and Antonella Vottari, the wife and sister of prominent 'Ndrangheta boss, Francesco Vottari, who was arrested in October 2007, were among those arrested Friday.

Prosecutors said those arrested faces ranging from murder to the illegal detention of firearms and explosives.

The seven suspects all allegedly belong to either one of two San Luca-based crime families, the Nirta-Strangio and the Pelle-Vottari.

The families have been locked in a bloody feud since the early 1990s. Victims are believed to include the six killed in Duisburg.