Horrified Thai factory workers found human legs in a shipping container that arrived from the United States.

The 20ft long metal box was packed with cardboard to be recycled at a depot in Chonburi in the east coast of the country.

But when staff emptied out the contents, they were shocked by the grim discovery on Tuesday afternoon, December 19.

Two human legs - still with socks and trainers - were seen on the ground in between the pieces of recyclable cardboard.

Pictures show how the flesh had rotted and just the knee joints, shin bones and feet bones were in tact. The person had been wearing long black socks and black flat-soled sports shoes with pink laces.

Forensic police officers collected the famines and are now searching through the items for other limbs.

Police Lieutenant Colonel Dechanut Thayasirichuti of the Si Racha police said: 'We do not believe that the remains are from a local Thai person. The body had already decomposed, so we believe it had been in the container for a long time before it arrived in Thailand.

'We suspect that the person was a foreigner and the remains travelled here. The shipping company will co-ordinate with foreign police.'

Factory workers called the emergency service and officers were alerted about the stomach-churning discovery at around 1 pm.

Cops went to the scene to take photos and retrieve the legs for investigation. The severed limbs have been sent to the Forensic Science Institute at the Police Hospital in Bangkok.

The shipping company and the U.S. Embassy in Bangkok have also been informed.

A factory worker told local media he was sorting through the pressed cardboard boxes when he found the rotting legs concealed underneath.

He said: 'I thought the bones were white poles. But then I saw the knees and the trainers. I was shocked when I realised they were from a human.'

Authorities said they were investigating if the person believed to be a foreigner died in an accident or was murdered.

Police Lieutenant Colonel Dechanut added: 'It is possible the person was the victim of a murder. It did not happen in our country though.'