Ukraine is threatened by revenge, which will throw it into the past, incumbent President Petro Poroshenko and presidential candidate has said.

"From the statements of my opponent and from the presentation of his team, unfortunately, the image of Little Russia is emerging. Today, our Ukraine is threatened with revenge, which can throw the entire state into the past, discard the ideas of freedom, dignity and a European future," Poroshenko said, speaking to supporters on Kyiv's Independence Square on Friday.

The president said there are high stakes in the presidential elections – whether Ukraine could continue its path to the European Union and NATO or these efforts will be "deflated."

"And another very important question: will Ukraine allow revenge? Can we resist the Kremlin's attempts to conquer Ukraine again and make it a part of the Russian Empire, if not part of it," Poroshenko said, adding that all Ukrainian citizens should think about saving the country.

Poroshenko said the main task of the head of state is not to make Russian President Vladimir Putin laugh, or to "fall to his knees, as some may think, and not to go fishing with him." He said the president must act firmly and decisively to protect Ukraine's national interests and the security of every citizen.

"If my opponent was scared to go to the debate with Poroshenko, where will he get the strength to deal with Putin?" he said.

Poroshenko said "Putin will face failure" in Ukraine five years from now if he is re-elected.

"We, dear friends, our team, will pass the point of no return, and no one will ever again see Ukraine in the embrace of Russia and we will enter the European Union. Now the issue of national security is more important for us than ever to resist the Russian scenario

"We need firm political will, firm ideological principles, diplomatic skills and experience, an experienced commander-in-chief of Ukraine's Armed Forces," he said.