Thai police have issued arrest warrants for two Americans who attempted to mail a preserved baby's head, foot and other human body parts to the United States, saying the objects were stolen from a medical museum in Thailand.

Police on Tuesday issued the warrants for Ryan McPherson, 31, and Daniel Tanner, 33 on charges of theft, possessing stolen items and falsely declaring the items on shipping documents.

The pair left Thailand on Sunday for neighboring Cambodia after police questioned and released them without charges. They told police they had bought the items at a Bangkok night market. On shipping documents they described the items as toys.

On Monday, a major Bangkok hospital said the objects were stolen from two of its museums, which the men had visited last Thursday.