Former U.S. marine Paul Whelan, who was detained by Russia's FSB security service on suspicion of spying, stands inside a defendants' cage during a court hearing in Moscow, Russia January 22, 2019. REUTERS/Maxim Shemetov

MOSCOW (Reuters) - Russia’s Federal Security Service (FSB) has extended by three months its investigation into former U.S. marine Paul Whelan who is being held on suspicion of spying, Interfax news agency cited Whelan’s lawyer as saying on Friday.

Whelan, who holds U.S., British, Canadian and Irish passports, was detained in a Moscow hotel room on Dec. 28. He denies the charges against him. A court in Moscow had previously ordered he be detained until Feb. 28.

“The investigation has been extended until May 28,” Whelan’s lawyer was quoted as saying.