A Ukrainian man who pretended to be a teenager, and attended a US high school using his false identity, has been handed a two-month sentence for passport and social security fraud.

Artur Samarin enrolled at Harrisburg High School in Pennsylvania when his visa ran out four years ago.

He was in his early 20s, but pretended to be an 18-year-old student named Asher Potts. He became actively involved at the school, working with a student advisory group on a food bank.

He now faces further time in prison or possibly deportation amid separate charges of fraud and sex crimes - including allegations he slept with a 15-year-old girl when he was 22.

He originally came to the US on a visa entitling him to work at a restaurant in the Hershey-Harrisburg area. The visa expired in 2012.