US soldier detained in Russia pleads guilty, official says

LONDON -- Gordon Black, the U.S. soldier detained in Russia, has admitted guilt on a theft charge, a Russian official confirmed to ABC News.

Black has pleaded guilty and is cooperating with the investigation, the Department of Internal Affairs of the Primorsky Territory told ABC News.

"Black has pleaded guilty and is cooperating with the investigation. Communication is carried out with the help of an English translator. The investigation continues," said Irina Syrova, a representative of the department, in a phone conversation with ABC News.

Black was detained in Vladivostok, Russia, earlier this month on charges of criminal misconduct, according to the U.S. Army. His detention is expected to last util at least July 2, according to the court. His lawyer had appealed his detention last week.

Two U.S. officials told ABC News this month that Black, a staff sergeant, had been stationed in South Korea before going on temporary leave. He was not granted permission to travel to Russia, the officials said.

Black had traveled to Russia to visit his girlfriend, the 35-year-old's mother, Melody Jones, told ABC News' "Good Morning America" last week.

TASS reported on Thursday that Black and the woman had a disagreement while he was visiting her in Vladivostok, a far-eastern city near the borders with China and North Korea.

"After Black left, his friend discovered the missing money and turned to law enforcement for help," TASS reported. "The police found the suspect in the theft in one of the city hotels."

Black had purchased a return flight, the outlet said.

ABC News' Ellie Kaufma, Joe Simonetti, Leah Sarnoff, Mark Guarino and Anne Flaherty contributed to this report.