NEW YORK (AFP) - An American who illegally imported dinosaur skeletons from Mongolia - one of them 70 million years old - was sentenced on Tuesday to three years in prison, authorities said.

Eric Prokopi, who pleaded guilty back in December 2012, was accused of ordering from Mongolia and then carefully rebuilding a 70-million-year-old Tarbosaurus bataar (T-bataar) skeleton. At 2.43m tall and 7.31 m long, the skeleton was sold at auction for US$1.05 million (S$1.32 million) on May 20, 2012 in New York. But after a tip from authorities in Mongolia, it was confiscated a month later. The skeleton was returned to Mongolia in May 2013.

Prokopi, 39, was accused of illegally importing in 2010 and 2012, several dinosaur bones for US$200,000 from a seller in the Asian nation, along with a British partner.

The bones were shipped through Britain to the United States, where the skeletons were reassembled, prosecutors said. He imported three T-bataar skeletons, as well as two from the saurolophus angustirostris, and several of oviraptors, they added.