Opposition leader Viktor Yushchenko's team said on Thursday it had filed a complaint to Ukraine's Supreme Court over the conduct of officials overseeing a contested presidential election. "Today we filed a complaint to the Supreme Court over the actions of the Central Election Commission," an official at Yushchenko's headquarters said, a day after the commission declared Prime Minister Viktor Yanukovich president. The Supreme Court confirmed the complaint had been received. Yushchenko says he was denied victory in the vote by mass fraud.