The leaders of Russia,
Ukraine, Germany and France aim to meet in Belarus's capital Minsk on
Wednesday to discuss a peace plan for eastern Ukraine.
It comes after leaders of the four countries discussed the ongoing conflict by telephone on Sunday.
More than 5,300 people have been killed by fighting between Ukrainian forces and pro-Russia rebels since April 2014.
Western countries accuse Russia of arming the rebels and sending troops to Ukraine - claims Russia denies.
German Chancellor Angela Merkel and French President Francois Hollande have been leading efforts to establish a new peace plan.
The detailed proposals of the peace plan have not been released, but the plan is thought to include a demilitarised zone of 50-70km (31-44 miles) around the current front line.
Mrs Merkel, Mr Hollande, Ukrainian President Petro Poroshenko and Russian President Vladimir Putin held an "extensive" telephone conference on Sunday, German government spokesman Steffen Seibert said in a statement.
The four parties discussed "a package of measures" to try to reach "a comprehensive settlement of the conflict in eastern Ukraine", Mr Seibert said, adding that the leaders aimed to meet on Wednesday.
Mrs Merkel and Mr Hollande (right) met Mr Putin in Moscow on Friday
Signatories of a previous ceasefire deal - Ukraine, Russia, rebel representatives and the Organization for Security and Co-operation in Europe (OSCE) - would also meet in Minsk on Wednesday, Mr Seibert said.
That deal, which was signed in Minsk last September, failed to end the fighting and the rebels have since seized more ground.
The pace of diplomatic activity to reach a deal to resolve the Ukraine crisis has been dramatically accelerating. With the German Chancellor Angela Merkel in the driving seat and French President Francois Holland as her co-pilot, the drive is on for a deal.
However, while few details have been provided, this is not a substantially a new peace plan.
When I spoke to the British Foreign Secretary Philip Hammond on Saturday he was reluctant to even go so far as labelling it as "Minsk Plus". A deal is still an aspiration rather than an approaching reality.
The level of frustration many western countries feel against Russia's policies has been palpable - Mr Hammond for example branded Vladimir Putin as "some kind of 20th-Century tyrant".
The heady optimism surrounding last year's deal evaporated quickly. This year people are much, much more cautious.
The latest push for a peace deal is thought to be spurred by news that the US is considering sending defensive weapons to Ukraine.
The move is opposed by many European leaders.
Speaking on Sunday, US state department spokeswoman Jen Psaki said the US remained concerned about fierce fighting reported in the cities of Debaltseve and Mariupol in Ukraine's east.
"We call on all parties to refrain from actions that undercut the current diplomacy," she added.
More than a million Ukrainians have fled their homes since April 2014, when the rebels seized a big swathe of the Luhansk and Donetsk regions following Russia's annexation of Crimea.
