RUSSIAN president Vladimir Putin and Ukraine's president Petro Poroshenko yesterday agreed in a telephone call that a ceasefire in eastern Ukraine was generally holding - but said further steps were needed to make it more durable.

The ceasefire between Ukrainian government forces and pro-Russian separatists took effect on Friday evening as part of a wider peace plan aimed at ending five months of fighting in eastern Ukraine in which at least 2600 people have died.

A statement yesterday from Poroshenko's office said the two leaders "also stressed the need for the maximum involvement of the Organisation for Security and Co-operation in Europe (OSCE) in monitoring the situation ... and for co-operation in providing Ukrainian and international humanitarian help".

An uneasy calm prevailed in eastern Ukraine yesterday after the ceasefire agreement. Residents and combatants said they did not expect the ceasefire to last long, but there were no reports of serious violations.

Despite the peace deal, the European Union has announced new economic sanctions against Russia to be implemented tomorrow over its role in Ukraine but said they could be suspended if Moscow withdraws its troops and observes the ceasefire.

Some provisions will make it harder for Russian state-owned firms to raise finance in the EU. A further 24 people were added to a list of those barred from entry to the EU and whose assets in Europe are frozen.

Russia's foreign ministry responded angrily to the measures, pledging unspecified "reaction" if they were implemented.

Moscow responded to a previous round of US and EU sanctions by banning most Western food imports.

At the two-day Nato summit in Wales last week, US President Barack Obama and other leaders urged Russia to pull its forces out of Ukraine.

Plans were also approved to create a rapid response force to counter Russian aggression with a headquarters in Eastern Europe that could act quickly if an alliance country came under attack.

Ukraine is not a Nato member, but the alliance has been alarmed by Russia's actions in Ukraine, and Russia is under both US and EU sanctions for its support of the rebels.

"It sends a clear message to any potential aggressor: Should you even think of attacking one ally, you will be facing the whole alliance," Nato secretary-general Anders Fogh Rasmussen said.

After attending the Nato summit, Poroshenko said: "I am sure that Ukraine as a state and I as leader of that state are doing everything possible to achieve peace in our country."

The peace roadmap, approved in Minsk by envoys from Ukraine, the separatist leadership, Russia and Europe's OSCE security watchdog on Friday, includes exchange of prisoners of war.

The prime minister of the rebels' self-proclaimed "Donetsk People's Republic", Alexander Zakharchenko, had said his side would hand over PoWs to Ukraine.

"We hope that on Monday, Ukraine will hand over its POWs," he said.

The spokesman for Ukraine's National Security and Defence Council, Andriy Lysenko, said his side wanted the exchange as soon as possible but gave no timeframe. He said the rebels were holding more than 200 Ukrainians captive.

The peace deal also envisages the creation of a humanitarian corridor for refugees and aid.

But the two sides remain far apart on the future status of the rebel-held areas in eastern Ukraine.

In rebel-held Donetsk, separatist commanders said they did not believe the five-month war was over.

"The ceasefire is looking good for now but we know they [the ­Ukrainian side] are only using it to bring in more forces here and ammunition, and then to hit us with renewed strength," said a rebel commander nicknamed Montana.

Meanwhile, a top Ukrainian clergyman says Putin has fallen under the spell of Satan and faces eternal damnation unless he repents.

The unusual statement on the first day of the ceasefire was made by Patriarch Filaret, who heads the Kiev Patriarchate, a branch of the Orthodox Church that broke away from Moscow in 1992 after the fall of the Soviet Union and the declaration of an independent Ukraine.