The 50,000-year-old remains of a baby mammoth uncovered by melting permafrost have been unveiled to the public by researchers in Russia's Siberia region who call it the best-preserved mammoth body ever found.

The findings are unique because the mammoth's head and trunk survived all these years. The trunk typically thaws first and is eaten by birds.

A baby mammoth that lay almost perfectly preserved for 50,000 years in the now-melting permafrost of eastern Siberia has been unveiled by a team of scientists.

A Moscow court has on Tuesday sentenced a US citizen to 15 years in prison on espionage charges, according to state-run news agency RIA Novosti.