Police have arrested 110 people in Britain, Spain, Serbia and the United States in a swoop targeting financial fraudsters.

Police raided 35 properties in the four countries in connection with "boiler room" gangs who dupe victims into buying worthless or nonexistent shares.

Of the arrests, 84 were in Spain, 20 in Britain, four in Serbia and two in the U.S. Most were on suspicion of money laundering and fraud.

About 300 police in Spain and 40 in London carried out raids in Barcelona, Madrid, Marbella and London.

City of London Police Commander Steve Head said the suspects had stolen millions of pounds from more than 1,000 victims, many of them British retirees.

The raids earlier this week were made public Friday after a Spanish judge lifted a reporting ban.