"The legitimacy of the presidential election in Russia and the allegedly elected candidate is questioned not only by the unlawful conduct of voting in the temporarily occupied Crimea. It was, in general, a political farce that has nothing to do with elections in the democratic sense of this process," Poroshenko said, according to a statement on his website.
The Ukrainian president called the vote "a choice without choice" and "without real political competition."
The Shanghai Cooperation Organisation (SCO) observers said that the election was organized in accordance with the principles of openness and transparency. The observer mission from the Commonwealth of Independent States also said that the Central Election Commission of Russia adhered to transparency requirements.
Poroshenko urged his international colleagues to ramp up pressure on the Kremlin. According to the Ukrainian president, Kiev will compile a list of those who helped organize the Russian presidential election in Crimea.
The latest data indicate that the turnout at the election reached 67.49 percent across Russia. Incumbent President Vladimir Putin is ahead with 76.66 percent of the vote with 99.84 percent of ballots counted.
According to the Crimean election commission, the final results of the election in the region saw Putin win with 92.15 percent of the vote.
Crimea rejoined Russia in 2014 after a referendum, where more than 90 percent of the local residents voted in favor of the reunification. Ukraine and a number of Western countries have not recognized the decision of Crimean voters. Russian officials have repeatedly pointed out that the referendum took place in accordance with the international legal framework.