A Massachusetts man is accused of sexually assaulting a young woman who was sitting next to him on a United Airlines flight from Tokyo to Washington last summer, according to charges filed this week in federal court in Alexandria.

Georgiy Seryogin, 47, who authorities say has U.S. and Russian passports, is charged with abusive sexual contact. He appeared Wednesday for a detention hearing and was released after posting bond.

According to court records, Seryogin was in a window seat on the July 27 flight and allegedly began molesting the 19-year-old woman as she was drifting in and out of sleep. The court papers say she began crying and pushed him off before reporting the incident to a flight attendant.

Seryogin spoke to FBI agents after the plane landed at Dulles International Airport and acknowledged that he had lifted the armrest between the seats and spread a blanket over the two of them, according to court papers. But he said that if he touched her, it was only because he moves in his sleep. The woman told the authorities that she could tell he was awake when she pushed his hands away.

Reached by phone, Seryogin declined to comment on the case.