Police in northern Italy have detained three men, including one linked to a neo-fascist Italian political party, after uncovering a huge stash of automatic weapons, material featuring Nazi symbols and a three-metre missile.

Police said the discoveries stemmed from a previous investigation into Italians who took part in the Russian-backed insurgency in eastern Ukraine.

In a statement on Monday, Turin police said one of the men arrested, Fabio Del Bergiolo, had run unsuccessfully in 2001 as a Senate candidate for the neo-fascist Forza Nuova party.

At his home in Gallarate, police found nine assault weapons, nearly 30 hunting rifles, pistols and bayonets as well as ammunition and antique Nazi plaques featuring swastikas.

Swiss citizen Alessandro Michele Aloise Monti and Fabio Amalio Bernardi, an Italian, were also detained after police found a three-metre long air-to-air French-made Matra missile in the hangar of Rivanazzano Terme airport in the Lombardy region. The men were allegedly seeking to sell the missile.

“During the operation, an air-to-air missile in perfect working order and used by the Qatari army was seized,” police said of the 245kg (540lb) Matra missile.

“This is a significant seizure, with few precedents in Italy,” said Turin police commissioner Giuseppe De Matteis.

The missile, 3.54 metres (more than 11ft) long was made in France and Del Bergiolo had been hoping to sell it for 470,000 euros (£423,000), according to Italian media reports.

The missile was “without explosive charge, but re-armable by people specialised in the field,” police said.

Carlo Ambra, the chief of the Turin unit of Digos, the police squad that deals with cases involving organised crime and terrorism, said investigators intercepted phone conversations between one of the men and an arms expert who proposed purchasing the missile on behalf of a third party.

“The intermediary was Del Bergiolo,” Ambra said, adding that investigations were ongoing. “The most important thing for now is that we managed to block the sale of these arms.”

The Mantra Super 530 F was a modernisation of the R530 missile that went into service in 1980, and has a range of 25km (15 miles), with an explosive charge of 30kg.