Dozens of homes have been raided in an international police investigation into the theft of valuable rhino horns.

An organised crime gang, linked by European security chiefs to a large traveller family originally from the west of Ireland, is believed to have netted goods and artefacts worth €40m in a string of robberies.

Armed gardaí and officers from the Criminal Asset Bureau (Cab) raided homes in the Rathkeale and Raheen areas of Limerick and in Newmarket in Cork.

One of the gangs suspected of involvement in the thefts has been nicknamed the Rathkeale Rovers.

A large amount of documentation, a small amount of cash, some artefacts and paintings were recovered and confiscated during the operation.

No arrests were made.

The Garda press office said that the raids were targeted on the three towns as part of the ongoing investigation into the assets and financial affairs of a gang suspected of extensive criminality.

They are involved in labour exploitation, counterfeiting, tarmac scams, tobacco smuggling and the theft of rhino horns and rare Chinese cultural artefacts, Europol have said.

Over the last three years, there have been more than 60 recorded thefts of rhino horns and Asian art from museums and private collections across Europe.

For the last two years, Europol has been tracking a suspected Irish organised crime gang which it warned was one of the most significant players in the illegal global trade in rhino horns.

They are wanted over robberies in Italy, Germany and the UK. They are believed to have links to North and South America, China and Australia and use “intimidation and violence” in their activities.

Cab officers have been involved in the Europol initiative to target the international crime gang.

Agencies in the UK, including the Serious Organised Crime Agency (Soca) and local police forces, have carried out more than 30 searches, including some in Northern Ireland, as part of the investigation.

Police in Britain, Italy, Belgium, Germany, Sweden, Portugal and France have all linked the theft of rhino horns to Ireland.

The Garda press office said the raids in Rathkeale, Raheen and Newmarket were carried out to gather evidence.

The latest rhino horn theft hit museum bosses in Ireland in April this year, despite them being put into storage for safekeeping.

Three masked men broke into the National Museum of Ireland’s Collections Resource Centre (CRC) in a warehouse in north Dublin and tied up a security man before leaving an hour later with four rhino heads holding eight horns.

Due to the level of the robberies, some European museums have replaced the real rhino horns with copies and some of these were stolen, one in Germany.

Rhino horn, which consists only of keratin, is sold in Chinese traditional medicine and claimed to be anything from an aphrodisiac to a cure for a hangover or cancer or even just a decoration.

Conservationists warn those using the illegal product that they would be better off biting their nails.