"Recent events of renewed shelling in Donetsk and Luhansk regions in southeastern Ukraine cause grave concern and, for all intents and purposes, jeopardize the peace process based on the September 19, 2014 Minsk memorandum," Putin's message, outlined on the Russian Channel One, said.
In his message to Poroshenko, received by the Ukrainian President on January 16, Putin also proposed a plan for the withdrawal of heavy weaponry from eastern Ukraine, but it was rejected by Kiev.
"We are ready to work with the OSCE to monitor the implementation of these [ceasefire observance] steps," the Russian president's message outlined.
In addition to calling on immediate suspension of hostilities by the warring parties, Putin's message to his Ukrainian counterpart included a proposal to withdraw heavy weaponry from the contact line established on September 19, 2014 in Minsk.
"I propose both sides… to take urgent measures toward discontinuing mutual attacks, as well as to immediately withdraw [heavy weaponry]," the Russian president's message added.
Earlier on Sunday, Kremlin spokesperson Dmitry Peskov said Poroshenko has rejected Putin's proposal, all the while resuming military action in southeastern Ukraine.
The withdrawal of heavy artillery is stipulated by the agreements signed last year in September during a meeting of the Contact Group on Ukraine in Minsk, attended by representatives from Kiev, the self-proclaimed People's Republics of Donetsk and Luhansk (DPR and LPR) and Russia.
The agreements were part of a memorandum which specified the implementation of a ceasefire, reached between Ukraine's conflicting sides during an earlier Minsk meeting of the Contact Group.
Despite the Minsk agreements, fighting has continued in southeastern Ukraine and clashes between independence fighters and Kiev forces have intensified in the past few weeks.
Kiev launched a military operation in southeastern Ukraine in mid-April, 2014. Since then, over 4,800 people have been killed as a result of fighting in the region, according to the United Nations.
