During Normandy Four talks (Ukraine, Germany, France and Russia) held on Monday by telephone Ukrainian President Petro Poroshenko called on the Russian side to immediately end aggression and to stop supplying weapons to the occupied territories.

"Ukraine's president said the past several days of July were some of the bloodiest in 2017 and called on Russia to immediately end aggressive actions and supplies of weapons to the occupied territories," Poroshenko's press service said.

The interlocutors noted the importance of a full ceasefire, the withdrawal of heavy weapons and separation of opposing forces with the 24/7 monitoring of the situation carried out by the Special Monitoring Mission (SMM) of the Organization for Security and Cooperation in Europe (OSCE).

The Normandy Four leaders listened during the talks to briefings by SMM Chief Monitor Ertugrul Apakan and his deputy Alexander Hug.

"Poroshenko noted the importance of introducing to Donbas a United Nations peacemaker mission. He repeated that the release of hostages is being blocked by the Russian side. Ukraine demands the immediate release of all hostages, as well as those being held in Russia, including Oleh Sentsov and Roman Suschenko," the press release says.

The sides agreed to set final steps for ensuring security and to continue work on the so-called Road Map for implementing the Minsk agreements.

The talks lasted about two hours.