Kolesnykov was in Kyiv to answer charges in court. He is accused of attempting to illegally seize shares of an unnamed Donetsk-based company. The court session was held behind closed doors.
Earlier today, Yanukovych demanded the immediate release of Kolesnykov. He threatened that his party and millions of its supporters will start a political strike if Kolesnykov is not released from custody immediately.
The authorities, however, have insisted that Kolesnykov's arrest was above board.
Interior Minister Yuriy Lutsenko, speaking in Ukraine's parliament, said that Kolesnykov was arrested in accordance with the law on various charges, including extortion and conspiracy to commit murder.
"If the investigators or the court find that Kolesnykov is a law-obeying citizen who has been illegally accused of violating the [Criminal Code], then, without doubt, I, as the minister, will beg [Kolesnykov's] pardon," Lutsenko said. "And everyone who acted unprofessionally during the investigation will be punished. I guarantee this. But on the other hand, I guarantee that if the investigators believe that Kolesnykov and other well-known figures from Donetsk are guilty, the case will go to court."
Others officials concur with the opposition that Kolesnykov has been unfairly treated.
Nina Karpachova, Ukraine's ombudswoman, admitted that the authorities have violated Kolesnykov's rights.
"Undoubtedly, the detainee's rights have been violated," Karpachova said. "There was a brutal violation of the detainee's right for direct access in the court. We all must know that! Tomorrow, it will concern your associates, your children, your relatives!"
Yanukovych today sent a letter to Prosecutor-General Svyatoslav Piskun, Supreme Court Chairman Vasily Malyarenko, and Interior Minister Lutsenko demanding Kolesnykovs immediate release.