US federal agents have arrested 47 people suspected of smuggling hundreds of South Korean women into the country to work as prostitutes in brothels and massage parlours, officials said today.

The arrests, which came late on Thursday in a series of raids in the Californian cities of San Francisco and Los Angeles, aimed at cracking what officials believe was a massive sex smuggling network.

Around 150 women, believed to be victims of the smuggling syndicate, were taken into protective custody as agents tried to establish how they were brought into the country and how they were treated.