SYDNEY, Dec. 11 - President Petro Poroshenko on Thursday pleaded with Russia to withdraw its troops from his country and close the border, saying it would lead to almost immediate peace, AFP reported.

His comments came as a day-old ceasefire that aims to end eight months of brutal war in the east of Ukraine largely held along the bloodied frontline on Wednesday.

But hopes of peace talks, due to start at the same time as the ceasefire, and the pulling back of heavy weaponry to create a 30-kilometre (20-mile) buffer zone remain in the balance.

Poroshenko, on a visit to Australia, said Russia must abide by a peace plan agreed in the Belarussian capital Minsk on September 5.

The Russian-brokered ceasefire that the rebels and a Kiev envoy signed then was meant to establish the 30-kilometre buffer between the fighters and grant limited self-rule to the separatists.

But hostilities only intensified after the two rebel regions -- the self-proclaimed People's Republics of Luhansk and Donetsk -- held their own leadership polls on November 2 that were denounced by both Kiev and the West.

"Please stop the fire. Please release the hostages. Please withdraw your troops from my territory," Poroshenko said in a joint press conference with Australian Prime Minister Tony Abbott.

"Please close the border. And I promise if you close the border, within one, two, three weeks, we have peace and stability in Ukraine. Very simple."

Russia denies giving military backing to the rebels in Ukraine but Kiev and Western governments have presented an abundance of evidence to the contrary.

The Western-backed Poroshenko said Russia was isolated globally.

"I just want to make it clear, Ukraine makes a war not only for our own independence, not only for the territorial integrity, we're making war for freedom, democracy, for peace," he said.

"The whole civilized world, European Union, Australia, Canada, United States, Japan, the whole world is together with Ukraine and Russia stays in isolation."

Abbott reaffirmed Australia's support for Ukraine in its fight against pro-Russian separatists.

"Australia feels deep solidarity with the free country of Ukraine and wishes to do whatever we reasonably can to support Ukraine," he said. (afp/ez)