A Russian man has been sentenced to 12 years and six months in prison on treason charges, security servicessaid Thursday, in the latest case involving alleged attempts to pass sensitive information to Ukraine.Vyacheslav Mamukov, from the Far East city of Khabarovsk, was accused of trying to sell state and commercial secrets related to transport infrastructure facilities to the Ukrainian secret services online, the Federal Security Service (FSB) said in a statement.The FSB said Mamukov had access to state secrets due to the nature of his job, though it did not disclose what line of work he was in.FSB video published by the state-run TASS news agency showed agents raiding an office and detaining Mamukov at his workplace.It was unclear when Mamukov was detained, but the FSBs assertion that his sentence has entered into force suggests the court ruling may have come weeks earlier and that its appeal failed.According to the Kommersant business daily, the Khabarovsk regional courthanded Mamukov the prison sentence and the Fifth Court of General Appeals rejected his appeal.Mamukovs lawyers disputed the length of his sentence, Kommersant said.Both the trial and the appeal hearing were held behind closed doors.The FSB said Mamukov proactively contacted representatives of the Ukrainian secret service via the internet with offers to sell information that could be used to the detriment of Russias security.