Ukrainian Prime Minister Mykola Azarov made an unexpected appearance Friday to give evidence as a witness at the trial of his predecessor Yulia Tymoshenko. Tymoshenko is charged with abuse of power linked to gas contracts she signed with Russia in 2009, in a case which could see her barred from politics and even jailed for up to a decade. But the hearing started in a farcical manner with Tymoshenko insisting she needed a Russian to Ukrainian translator to understand the comments of Azarov, who normally speaks in public in Russian. "I do not understand Russian," said Tymoshenko, who always speaks in Ukrainian in public although she is known to have a good command of Russian. "Please give me a translator for the prime minister of Ukraine, who does not speak Ukrainian," added the politician. One of the leaders of the pro-Western Orange Revolution in 2004, Tymoshenko narrowly lost to her old rival Viktor Yanukovych in presidential elections last year and has alleged the trial is a vendetta pursued by the president. Azarov, a number-crunching bureaucrat rarely seen out of a suit, is seen as a faithful ally of Yanukovych and served as his deputy when the current president was prime minister. Tymoshenko is accused of sustaining a loss to Ukraine's budget of 1.5 billion hryvnias ($190 million) when she signed a new energy contract with Russia after a brief interruption of gas deliveries in 2009. It was not immediately clear who had called Azarov as a witness but his evidence appeared to be set to back up the case of the prosecution. Tymoshenko signed the contracts with Russian Prime Minister Vladimir Putin and Azarov said he had personally asked the strongman how Moscow could have signed a deal that was so disadvantageous for its neighbour. "He replied that he did not understand the reasons himself and it would be better to ask the Ukrainian officials who were supposed to be representing the interests of Ukraine," Azarov said. Azarov said that the current government was looking at how to revise the contracts. Known as Ukraine as the "Iron Lady" after her heroine ex-British prime minister Margaret Thatcher or sometimes as just "Vona" ("She"), Tymoshenko was briefly imprisoned in 2001 on forgery charges that were eventually quashed. The current charges carry a sentence of between seven and 10 years in prison. But even if she escapes a jail sentence, any guilty verdict would disqualify her from parliamentary polls next year and the next presidential elections in 2015.