Yanukovych called for a constitutional assembly to draft a new constitution. Jailed opposition leader and former Prime Minister Yulia Tymoshenko said Yanukovych is trying to solidify his dictatorship in a new constitution.
"He wants to make his absolute rule eternal, all the way to the introduction of hereditary rule," she said in statements on her Web site.
Yanukovych said the constitutional assembly would work to bring balance to the branches of government.
Tymoshenko is serving a seven-year prison sentence after a conviction on charges she abused her authority when she helped broker a natural gas deal with Russia's Gazprom in 2009.
Her daughter, Eugenia Tymoshenko, told U.S. lawmakers last week the former prime minister was mistreated in prison.
"My mother has been illegally imprisoned, maltreated and humiliated for six months by the regime which is trying to break her," she said in written remarks.
U.S. lawmakers told Eugenia Tymoshenko that Yulia Tymoshenko's continued detention was a "setback for democracy."