Italian police seized assets with estimated worth of 500 million euros (563 million US dollars) from a leading clan of "the Ndrangheta mob in the southern Calabria region" on Monday, local media reported.

The operation was ordered by prosecutors of the local Anti-Mafia District Directorate (DDA), and targeted at the Iannazzo crime family which is considered a powerful clan based in the region's third largest city of Lamezia Terme, Ansa news agency reported.

The seized assets included 53 plots of real estate and farmland, 24 commercial buildings, 27 vehicles and shares of at least 21 companies, the organized crime investigation group of Italy's finance police said in a statement.

Many of the assets were directly linked to local businessman Franco Perri who is allegedly a close associate of the Iannazzo clan.

The entrepreneur was thought to have developed "a solid and lucrative relationship with the Iannazzo family's current boss, up to the point of being considered as acting in collusion with the clan," the anti-mafia prosecutors told a press conference on Monday.

Overall some 65 people and 44 companies were involved in the investigation that resulted in the raids, local media reported.

Magistrates ordered no arrests, but decided to make a broad "preventive" seizure of the suspects' assets, which is a special procedure allowed by Italian anti-mafia legislation to target at the economic power of organized crime syndicates.

One of the region's largest shopping centers was among the properties taken by the Italian authorities.

The mall, which hosts hundreds of stores, will keep functioning after being put under the immediate administration of managers already selected by a court, the DDA office said.

The allegedly mafia-linked assets seized on Monday were spread across all provinces of the Calabria region.

The Calabria-based "Ndrangheta" is currently seen as the richest and most dangerous of the three main mafia groups in Italy, with an estimated 52.6 billion euros (59.2 billion US dollar) in annual turnover, according to a 2013 evaluation by Demoskopika research institute based on data from the Interior Ministry and Anti-Mafia Investigation Department.

Monday's major operation took place as Italy marked a day of remembrance for mafia victims.

The Italian authorities, anti-mafia groups and some 30,000 people gathered in Messina, Sicily, where a main commemoration for over 900 people killed by organized crime was held.