WASHINGTON, Jan 6: US authorities have alerted relief agencies working in tsunami-affected areas of the potential for human trafficking - especially of tens of thousands of children who have been orphaned by the disaster.

The State Department said the action followed media reports that thieves, rapists, kidnappers and scam artists are preying on tsunami survivors and families of victims in Asian refugee camps and hospitals. In some cases, homes of those people who disappeared in last Sunday's disaster have also been burgled.

"There are sufficient credible reports for us to conclude that this is a real danger and that decisive action must be taken now to prevent abuse," State Department's deputy spokesman Adam Ereli said at a briefing in Washington.

He said US authorities also have issued guidelines to officials and volunteers in the region to minimize the risk of human trafficking, asking them to register people who come to camps and ensure proper security for those sheltered.

The US guidelines focus on the most vulnerable group of women and children and urge relief workers to make special arrangements for their safety. Other instructions include protecting relief workers and increasing the general awareness of camp workers about dangers of human trafficking.

"We are appalled by these reports and horrified that thousands of children orphaned by this disaster are vulnerable to exploitation by criminal elements who seek to profit from their misery," Mr Ereli said.

News and warnings of crimes against tsunami victims have come in from places as far apart as Britain, Sweden, Sri Lanka, Thailand and Hong Kong. In Sri Lanka, a women's group, the Women and Media Collective, said women and children had been raped during unsupervised rescue operations and at camps.

Save the Children cautioned that children orphaned by the tsunami were vulnerable to sexual exploitation. In Thailand, thieves disguised as police and rescue workers have looted homes and hotel safes.