Russian President Vladimir Putin and his Ukrainian counterpart Petro Poroshenko have spoken by phone and "largely agree" on a possible way out of the Ukraine crisis, Interfax news agency reported, citing Putin's spokesman.
"The viewpoints of the presidents of the two countries largely coincide on possible ways out of the grave crisis situation," Dmitry Peskov was quoted as saying.
Ukraine's President Petro Poroshenko has said that he believes the crisis in the east of the country is very close to the point of "full-scale war".
He said that EU leaders agreed to prepare new sanctions against Russia, which could be implemented depending on the progress of his peace plan.
He added that he hopes a meeting with Russian amd EU representatives on Monday can bring about a ceasefire.
Ukraine president Petro Poroshenko has called on the European Union to give an "appropriate response" over Russian forces being brought into the country, his spokesman said on Twitter.
Ukraine's President Petro Poroshenko has said that Russian troops "came to the rescue" of separatist militants following advances by Ukrainian forces, the Interfax news agency reports.
The situation in the conflict zone in eastern Ukraine is difficult but controllable, the country's President has said according to the Interfax news agency.
President Petro Poroshenko also said that Russian and Ukrainian military officials have held their first consultations on the crisis.
Ukraine's President Petro Poroshenko has said that his country will face a constant military threat for the foreseeable future.
In a phone call to German Chancellor Angela Merkel, US President Barack Obama said that Russia had to take more steps to de-escalate the situation in eastern Ukraine.
Both leaders agreed that Russia should urge rebels to release hostages and end the flow of heavy weapons and fighters across the Russian border.
"The leaders agreed that to date neither the United States nor Germany has seen Russia fulfill these required actions," the White House statement said.
President and the Chancellor also reaffirmed their commitment to work together as well as to continue to support Ukraine’s long-term stability and prosperity, during the call.
US Vice President Joe Biden has told Ukraine President Petro Poroshenko that the United States was working with European leaders on further sanctions on Russia, over the escalation of the conflict in Ukraine.
"The leaders discussed Russia's ongoing support for the separatists and apparent escalation" the White House said in a statement about the call between the two men.
"The vice president told President Poroshenko that the United States was engaging with European leaders to discuss the imposition of costs on Russia for its continued escalation of the conflict," it said.
The Ukrainian president has again accused Russian army officers of fighting alongside pro-Moscow separatists in the east of the country.
Petro Poroshenko said: "Russian staff officers are taking part in military operations against Ukrainian forces."
The war of words between Kiev and Moscow followed a weekend of intense fighting, in which Ukrainian forces say they inflicted heavy losses on pro-Russian rebels.
A Ukrainian plane taking part in the military campaign against separatist rebels was shot down by a rocket "probably" fired from Russian territory, the country's defense minister was quoted as saying.
Speaking on the country's presidential website Colonel General Valery Heletey said crew members from the military transport plane had been in contact with the army's general staff.
He said that the plane was flying at a height of 6,500 meters and therefore could not have been brought down by weapons used by the separatists.
He added: "The plane was brought down by another more powerful rocket weapon which was fired, probably, from the territory of the Russian Federation."
There was no word on casualties, but a military spokesman was unable to confirm that everyone on board was alive.