The court sentenced Tymoshenko today (11 October) to seven years in prison for abuse of office in the negotiation of a gas deal with Russia in 2009, when she was prime minister.
According to the verdict, Tymoshenko will not be able to run in a parliamentary election due next year.
"I'm certain that the European court will cancel this unjust ruling," Tymoshenko said after the judge announced the verdict.
"Today the Constitution and justice in Ukraine are being trampled and no one can rely on these courts. This is a very difficult and important moment. Be together! Be strong! Glory to Ukraine!" Yulia Tymoshenko said as she left the courtroom, the Ukrainian information agency Unian reported.
Carl Bildt, the Swedish foreign minister and one of the architects of the Eastern Partnership initiative, aimed at deepening relations with Ukraine and other countries at the Union's eastern periphery, said in a tweet during an EU ministerial meeting that the court decision would "endanger the entire relationship" between Kyiv and Brussels.
Catherine Ashton, the High Representative for Foreign Affairs, stated that the Union was "deeply disappointed" by the verdict, which did not respect international standards as regards fair legal process, adding that the Union "would reflect" on its policies toward Ukraine.
"This unfortunately confirms that justice is being applied selectively in politically motivated prosecutions of the leaders of the opposition and members of the former government. It is especially disappointing for a country that currently holds the Chairmanship of the Committee of Ministers of the Council of Europe," Ashton stated.
Indeed, Ukraine is chairing the body's Committee of Foreign Ministers from 11 May to 7 November 2011. The organisation's activity is largely centred on human rights.
When asked by EurActiv whether this meant Ukrainian President Victor Yanukovych's 20 October visit to Brussels would be cancelled, a senior EU diplomat said such measures if taken would be decided by European Commission President José Manuel Barroso.
Political groups react
Wilfried Martens, president of the centre-right European People's Party, went further than Ashton, calling for the suspension of negotiations of the EU-Ukraine Association Agreement, which are expected to be concluded and signed in December.
"The promise of Yanukovych to European leaders to release political prisoners in order for them to stand for the elections, has yet to be fulfilled, which makes EU cooperation with the Ukrainian authorities extremely problematic," Martens said.
However, not all political groups reacted as promptly as the EPP. The Socialists and Democrats (S&D) group in the European parliament did not hurry to publish a statement.
On previous occasions, the S&D have taken a more relaxed stance vis-à-vis what was seen by other groups as democratic backsliding under Yanukovich.
Ukrainian officials remain optimistic
Speaking to journalists, the Ukrainian Minister of Foreign Affairs Konstiantyn Gryshchenko downplayed the effect of European pressure on his country. "I think that it's being taken seriously by many actors in Ukraine but it's not simply that someone tells us what to do and we immediately take salute," he said.
The Head of Mission of Ukraine to the European Union Kostiantyn Yelisieiev emphasised the international importance of the Association Agreement.
"At this stage to put the Tymoshenko case ahead of the strategic importance of the document is a great mistake … This time the EU should make a choice as to what is most important for them," he said
Yeliseiev remained optimistic on the outcome of negotiations. "The conclusion of the agreement with Ukraine will be a clear-cut signal that the EU still trusts in the European project … and in my view we are very close to a deal," he said.
Former ally criticises Tymoshenko
Some of Tymoshenko's detractors, including her then-ally during the 2004 Orange Revolution, the former President Viktor Yushchenko, consider that she has indeed acted against her county's interests by signing a highly unfavourable gas contract with Russia in 2009.
"Why has Germany got a base price of $250 per [1,000 cubic meters of gas], Slovakia and Austria have from $250 to $300, and Ukraine has $450," asked Yuschenko, as quoted by Interfax Ukraine.