Vitaliy Klitschko, leader of Ukraine's opposition party UDAR, said he believes the authorities want to keep him from running for president in 2015 because he is the main rival of incumbent President Viktor Yanukovych.

"The authorities are doing everything to destroy Yanukovych's main rival. They are scared," the opposition activist said in Kyiv's Independence Square on Thursday evening, commenting on the inquiry filed by the Central Elections Commission to the Ukrainian Constitutional Court for an official interpretation of the provisions of the Constitution outlining the requirements to parliamentarians and the president in terms of the duration of residence on the territory of Ukraine before elections.

Klitschko reiterated that the Central Elections Commissions inquiry is targeted against him. "I want to say that it's not going to work," he said.

"There are no legal grounds for that, and I am not scared," he said.

Klitschko earlier said he intends to run for president of Ukraine in 2015.