A close associate of former Yukos boss Mikhail Khodorkovsky has told a court that fraud charges levelled against him are "false".
Platon Lebedev (right) and Mikhail Khodorkovksy (left) are close allies
Platon Lebedev has been on trial alongside Mr Khodorkovsky since June in a case centring around the privatisation of a fertiliser firm.
The pair claim they are being punished by the authorities for the political ambitions of Mr Khodorkovsky.
Mr Lebedev said there were "absurd contradictions" in the case.
Opening his defence, he said he could not see the legal basis of the charges he faced, which also include allegations of tax evasion.
"To my embarrassment, I could not understand the file of complaints against me," he told a Moscow court.
Mr Lebedev headed the Menatep group, the parent company of Yukos.
Mr Lebedev and Mr Khodorkovsky, who each face a possible 10 year jail sentence if convicted, will be questioned by a judge over the next few days.
Mr Khodorkovsky began his testimony last week, telling the court that he objected to the way that the "running of a normal business has been presented as a work of criminal fiction".
The charges are seen by supporters as politically motivated and part of a drive by Russian President Vladimir Putin to rein in the country's super-rich business leaders, the so-called oligarchs.
Yukos has been presented with a $27.5bn (£13bn) tax demand by the Russian authorities and its key Yugansk division was auctioned off to part settle the bill.
The company's effort to gain bankruptcy protection in the US - in a bid to win damages for the sale - were dismissed by a court in Texas.