MOSCOW (AP) — A Moscow court has extended the detention for the American arrested at the end of December for alleged spying.

Paul Whelan, a former U.S. Marine, was detained in a Moscow hotel at the end of December. His arrest raised speculation that he could be swapped for one of the Russians being held in the United States. Whelan's lawyer said his client had been handed a flash-drive with classified information that he had been unaware of.

The court in Moscow ruled Friday to keep Whelan behind bars for another three months pending the investigation.

Meanwhile, the U.S. Embassy complained Friday that Russian investigators are not letting Whelan sign a waiver that would allow consular officials to release more details about his case.