The establishment of a Constitutional commission in Ukraine ushers in a new stage of the country's Constitutional reform, Ukrainian President Petro Poroshenko has said.

"The signing of this decree heralds a new and increasingly crucial stage of the Constitutional reform. The launch of these efforts will be a lengthy, important and necessary process," Poroshenko was quoted as saying on Tuesday by his press service.

"We must preserve the unity and integrity of Ukraine. We should leave no chance for those who seek so-called federalization, which actually means a break-up of Ukraine," he said.

The objective of the new commission will be to formulate suggestions aimed at updating the Ukrainian Constitution in order to be able to respond to challenges facing the country's society today, as well as meet its needs. Members of different political forces, public figures, as well as Ukrainian and foreign experts will be asked to contribute to this process. "Beyond any doubt, decisions to bolster the judicial branch of power and increase its independence, as well as decisions concerning anti-corruption measures aimed at the authorities, should be complemented by a highly important component - local governance reforms and reforms aimed at de-centralizing power," Poroshenko said.

These measures will also prompt the country's politicians to better fulfill their obligations as part of the de-centralization process, the president said.

Earlier on Tuesday, Poroshenko signed a decree establishing a Constitutional commission as an auxiliary agency operating under his auspices.