MINSK - Ukraine and pro-Russian rebels agreed a new truce deal Wednesday that goes into immediate effect and replaces one broken just hours after its signature at the end of last month.

The latest ceasefire was negotiated between Moscow and Kiev envoys in the Belarussian capital Minsk with the help of a senior negotiator from the Organisation for Security and Co-operation in Europe (OSCE).

Both Ukrainian and OSCE officials said the latest initiative was pushed forward by Boris Gryzlov — a former Russian parliamentary speaker whom President Vladimir Putin handpicked as his personal envoy to the negotiations earlier this month. Gryzlov is seen as both a close ally and confident of Putin who brings a much greater degree of credibility to truce talks that had been conducted by much lower ranking and less known Russian officials in the past year.

Ukrainian media cited sources as saying that Gryzlov had conducted a rare private meeting with Ukrainian President Petro Poroshenko in Kiev before heading off to Minsk. “Russian representative Boris Gryzlov proposed making another attempt at reaching a ceasefire,” Russian news agencies quoted OSCE negotiator Martin Sajdik as saying in Minsk.

“This proposal was supported by all of the meeting’s participants,” Sajdik was further quoted as saying. There was no immediate comment from Gryzlov himself or the representatives of Ukraine’s separatist Lugansk and Donetsk regions. A spokeswoman for Poroshenko’s peace negotiator said the new truce would go into immediate effect in honour of the “Old New Year” holiday that is celebrated Wednesday in ex-Soviet republics according to the Julian calendar.

“Ukraine stresses that without a ceasefire, there can be no de-mining or a proper solution to outstanding political, humanitarian and economic issues,” Ukrainian spokeswoman Darka Olifer wrote on Facebook. “That is why Ukraine supports the latest initiative of Russian representative Boris Gryzlov.”

Kiev’s pro-Western leaders and the insurgents are fighting over an industrial region the approximate size of Wales that is home to about 3.5 million people and the centre of the splintered former Soviet nation’s coal and steel wealth. Russia firmly denies allegations of orchestrating and backing the war in order to keep some leverage over Ukraine in the wake of its decision to establish closer trade and political relations with the European Union.

The previous “New Year and Christmas” truce was struck on December 22. It was broken the following morning and yet again failed to bring an end to a 20-month conflict that has now claimed more than 9,000 lives. Three Ukrainian soldiers and two rebel fighters have been reported killed since the start of the year.

The OSCE’s Sajdik said that the sides had agreed to meet again in Minsk next week in order to assess the degree to which Wednesday’s call for all sides to lay down their arms was being observed. He added that Ukraine and insurgency leaders had declared their intention to release a combined total of more than 50 prisoners of war as soon as all the technicalities had been resolved.

“The sides have agreed to provide more details about this no later than next week.” Poroshenko has repeatedly vowed to immediately return home hundreds of soldiers captured by rebel forces across the shattered war zone. The issue is one of many that has kept the foes from agreeing the terms of a final solution to one of Europe’s deadliest conflicts since the Balkans wars of the 1990s.

On the other hand, Relatives of those killed in the MH17 air disaster Wednesday urged Dutch Prime Minister Mark Rutte to launch a global campaign to obtain radar images which may help pinpoint who fired a missile at the plane.

All 298 passengers and crew onboard the Malaysia Airlines flight jetliner — most of them Dutch — died when it was shot down en route to Kuala Lumpur over war-torn eastern Ukraine in July 2014.

Officials with the Dutch safety board (OVV) concluded in their investigation last year that the Boeing 777 was hit by a Russian-made BUK missile fired from territory held by pro-Russian rebels. But they did not say definitively who pulled the trigger.

A separate criminal investigation is also underway in the Netherlands to try to find those responsible and bring them to justice. Now the Dutch relatives have written to Rutte to protest that primary radar data was not made available to the investigators by either the Russian or Ukrainian authorities.

“We can’t accept that people have refused to provide crucial information,” the families said in the letter, dated Tuesday and published Wednesday. They are urging Rutte to push either the United Nations or the International Civil Aviation Organisation (ICAO) to demand that the data is handed over.

The Dutch investigators acknowledged that while they were given certain radar data by both Kiev and Moscow, they had not received what is called the “primary radar” from either country. Primary radar, unlike secondary radar, can detect aircraft or unknown flying objects even if they are not equipped with a transponder, according to the ICAO.

That means primary radar could possibly trace the trajectory of a missile, for example. The Dutch investigators said in their October report that it was “very unlikely” that the primary radar systems in place could have detected the missile. But the families contended that that finding did not rule it out completely.

Under the ICAO regulations primary radar data should be kept for 30 days, and longer if it is needed for a crash inquiry. But Russian officials told the Dutch team they had not kept the data because the disaster did not happen in their territory. And Ukrainian authorities said their primary radar systems had been shut down at the time for scheduled maintenance.