Ukraine ceasefire holds so far as Poroshenko orders halt at dusk

A tentative ceasefire was holding in eastern Ukraine on Friday night after Kiev agreed a truce with separatist rebels that included a pullback of weapons and the release of prisoners; it held out the best hope so far for an end to a five-month conflict that has killed more than 2,000 people.

Ukraine's president, Petro Poroshenko, ordered government forces to stop fighting at dusk, while negotiators in Minsk finally came up with agreements on prisoner exchanges and the delivery of humanitarian aid, putting some substance on the fragile outline of the ceasefire.

But there was scepticism over whether the more radical elements on either side would obey the ceasefire, and concern in Kiev and western capitals that the truce would effectively "freeze" the conflict and give Moscow de facto control over the disputed chunk of eastern Ukraine that has been ruined by war this summer.

Barack Obama expressed doubts at the Nato summit that the truce would result in anything more substantial. "Obviously we are hopeful, but based on past experience also sceptical that the separatists will follow through and the Russians will stop violating Ukraine's sovereignty and territorial integrity. So it has to be tested," he said.

The UN secretary general Ban Ki-moon described the deal as a "positive step". But David Cameron told the Nato summit that a fresh round of sanctions against Russia, imposed for its heavy military involvement in eastern Ukraine, would still go ahead. "We need to look carefully at whether it is a ceasefire or whether it also includes a commitment, as I understand it might, to make real progress on a proper peace plan. We should be clear that the sanctions which we agreed last Saturday in Brussels will go ahead," he added.

"But, of course, if a ceasefire and a proper peace plan are put in place, then it'll be right to look and see how those sanctions could potentially be removed if proper milestones are reached."

Even as the ceasefire was promised, fighting continued in the outskirts of Mariupol, a strategic port city facing a possible rebel onslaught. There was heavy shelling during the morning, though the guns went quiet as the ceasefire time approached.

The Minsk agreement, agreed by former Ukrainian president Leonid Kuchma with leaders from the self-proclaimed Donetsk and Luhansk "republics", in the presence of officials from Russia and the Organisation for Security and Cooperation in Europe (OSCE), came two days after Russian President Vladimir Putin produced a seven-point peace plan, which he apparently jotted down on a flight to Mongolia, and involves Ukrainian forces moving artillery away from populated areas and the start of political negotiations.

It was not immediately clear whether Ukraine had agreed to all elements of Putin's plan before signing the ceasefire. Representatives of the separatist movement, which Kiev has repeatedly called "terrorists" in recent weeks, said the political status of the regions was not discussed in Minsk, but said they considered the territories would never again be part of Ukraine.

In turn, Russia's foreign ministry said Nato statements on Ukraine, as well as joint military exercises between Nato countries and the Ukrainian army would "undoubtedly lead to increased tension and threaten to end the progress in the peace process". In a statement, the ministry accused Nato of "supporting neo-fascist and extremist forces" in Ukraine.

Earlier on Friday, there was fighting on the ground near Mariupol, as rebel forces allegedly backed by Russian army soldiers advanced down the coast from Novoazovsk, a city near the Russian border that was seized last week. There had been heavy artillery fire overnight, though it was unclear whether the rebels wanted to push on to Mariupol before the peace talks started or were merely putting further pressure on Kiev to sign up to the peace plan. Ukrainian forces who had been at the frontline said they were convinced they were fighting against regular Russian soldiers rather than rebels.

Andriy Biletskiy, commander of the far-right Azov volunteer battalion, which has been doing much of the fighting around Mariupol, said the pro-Russia forces had been pushed back to 16 miles from the town, having reached three miles on Thursday. He said his fighters did not suffer any casualties overnight, but there were reports of civilian deaths, including two children in the villages along the road.

Tanks and other armoured vehicles from Ukraine's army arrived on Thursday evening, Biletskiy said, and despite coming under heavy artillery fire, the Ukrainians were able to repel the rebel advance.

As 6pm local time came, the Ukrainian frontlines were quiet, and a pair of tanks moved away from the front. Fighters relaxed, cleaning their weapons and eating chocolate bars, but were sceptical that the rebels would stop fighting. Biletskiy said he would obey the ceasefire if there were no further attacks from the pro-Russians, but hoped it would only be temporary: "What talk can there be of a ceasefire when the enemy is on our land?"

Just as the ceasefire was taking hold, a press conference with rebel leaders was announced in Moscow for next Tuesday, with the topics including "Why is the Ukrainian army not abiding by the ceasefire?" and "Results of talks on gas supplies between Russia and the Donetsk People's Republic", suggesting that Moscow may now deal with Ukraine's east regions as a de-facto independent state.

Biletskiy raised the possibility of volunteer fighters continuing a kind of partisan warfare to win back the regions: "As soldiers we will obey our orders but as citizens that will be hard."

One of his subordinates said: "We will use the ceasefire to regroup and retrain, and then we will take the land back."