Ukraine's Russian-backed separatists said they had agreed with Ukrainian officials on a ceasefire starting Friday, at peace talks in Minsk.

"Representatives of Ukraine and Donetsk People's Republic and Lugansk People's Republic signed a ceasefire protocol from 6 pm on Friday," the Twitter account of the so-called Donetsk People's Republic said, without providing further details.

Ukrainian President Petro Poroshenko announced that a ceasefire plan aimed at halting five months of conflict in the industrial east would be signed on Friday.

His comments, on the sidelines of a NATO summit largely devoted to the crisis in Ukraine, followed talks on a peace blueprint between Poroshenko and Russian President Vladimir Putin on Wednesday.

Islamic State militants have issued a threat to President Vladimir Putin, vowing to oust him and "liberate" the volatile North Caucasus over his support of the Syrian regime.

The General Prosecutor's Office of Russia demanded that access to the address, which was posted on YouTube on Tuesday and features what jihadists say is a Russian-supplied fighter jet, be blocked.

Russian President Vladimir Putin on Wednesday called on both Ukrainian rebels and government forces to cease fire and agree to the broad terms of a truce ending their four-month war.

Putin's first direct appeal on the insurgents to lay down their weapons came hours after the beleaguered Ukrainian president, Petro Poroshenko, said he and Putin had agreed on a ceasefire deal.

A comment attributed to President Vladimir Putin warning that Russia could capture Kiev in two weeks was taken out of context, his top foreign policy aide said Tuesday.

Ukrainian forces were forced to retreat from Lugansk airport in the face of a Russian troop attack and Moscow soldiers moved into key cities in the east on Monday, Kiev said, a day after Russian President Vladimir Putin evoked "statehood" discussions for the conflict-torn east.

Putin accused Europe of ignoring the Ukrainian military's "direct targeting" of civilians in the conflict and said the offensive pushed by insurgents there were simply an attempt to expel Kiev's forces from residential areas.

Russian President Vladimir Putin on Sunday raised the stakes in the Ukraine conflict by calling for the first time for statehood to be discussed for the restive east of the former Soviet state.

The remarks came just hours after the European Union gave Moscow -- which the bloc accuses of direct involvement in the insurgency -- a week to change course or face new sanctions.

He doesn't bluster and he doesn't strut and President Barack Obama certainly isn't panicking, though he admits it feels like the world is falling apart.

But Obama's cool-in-a-crisis style and disdain for the impulsive use of military force is fueling criticism of his leadership, as crises stagger the Middle East and Ukraine.

President Vladimir Putin called his Ukrainian counterpart Petro Poroshenko a "partner" and said in a televised interview recorded Friday that they have agreed on Russia's next aid delivery.

Putin said that his meeting with Poroshenko for marathon talks this week "was very good, that was my impression. It was quite frank," according to an extract of an interview to air in full on Channel One television on Sunday evening.

European Commission head Jose Manuel Barroso condemned Moscow's "significant incursions" into eastern Ukraine during a phone call with Russian President Vladimir Putin on Friday.

A statement from the commission said Barosso had a "very frank exchange" with Putin, in which he expressed his concern over Russia's direct role in fighting in eastern Ukraine.