A former US marine accused of spying in Russia has told the BBC's Sarah Rainsford he is "holding up well" after two months in custody but said he couldn’t comment publicly on the charge against him for fear of making his situation worse.

Paul Whelan, who also has British, Irish and Canadian citizenship, spoke while in a Moscow courtroom, where he was appearing for a hearing on extending his arrest.

He was detained in late December in Moscow after he was handed a flash drive which the FSB says contained state secrets.

Mr Whelan’s lawyer says he is innocent.

His detention in custody has now been extended until late May.