Thousands of Ukrainians serenaded opposition leader Yulia Tymoshenko outside her jail cell on Sunday in a special birthday concert aimed at showing the West that she still has strong support among the people. The former Orange Revolution leader marked her 51st birthday in prison after being convicted on abuse of power charges and jailed for seven years in a high-profile case that has badly strained Kiev\'s ties with the West. Tymoshenko describes her prosecution as a political vendetta launched against her by President Viktor Yanukovych after his narrow victory against her last year in a bitter national poll. The ex-premier has since been charged in a brand new case linked to alleged financial crimes committed in the 1990s, despite EU calls for Tymoshenko to be released. Several thousand people bearing roses and chanting \"Yulia! Freedom!\" snaked their way past barricades -- ostensibly set up for special road repairs -- to assemble outside the imposing gates to Tymoshenko\'s holding facility. A few dozen policemen watched nervously as the group set up a small makeshift stage near the prison wall and then danced in step and waved party flags as a few local bands performed songs for their jailed hero. \"Even behind bars, in inhumane conditions, Tymoshenko is keeping up her fight,\" Tymoshenko\'s second-in-command Oleksandr Turchinov told the crowd. Dozens of people taped red and white paper hearts to the grey brick walls of the prison, while others cheerfully drank champagne out of paper cups. Tymoshenko\'s daughter Yevgenia Carr -- who is married to a British rock musician and who sat at her mother\'s side during her dramatic sentencing in court -- said events like Sunday\'s made her optimistic about her mother\'s release. \"I want to wish her great health ... and for justice to quickly prevail,\" the 31-year-old told the throng of supporters. \"We will not let anyone break her spirits.\" Carr lamented however that her mother had been moved to a different jail cell that did not face the street after being photographed waving to the crowd on a previous occasion. The show of support came as Western pressure mounted on Yanukovych to release the opposition leader and several of her colleagues also jailed since being voted out of office. Yanukovych has argued that Tymoshenko\'s crimes were real and not politically motivated -- some of them dating back to probes begun by old administrations in the 1990s. But the European Union insists that it views these cases as political and will not negotiate with Ukraine on its potential membership -- something Yanukovych hopes to secure within a decade -- until the opposition leader is free. The EU\'s ambassador to Ukraine added last week that the two sides were now unlikely to seal an association agreement at a summit next month that was supposed to herald Kiev\'s post-Soviet commitment to Brussels. The December 19 Kiev event was thrown into question when local reports emerged that Yanukovych was preparing to travel to Moscow that day to negotiate the details of Ukraine\'s role in a new customs union led by Russia.