MOSCOW, June 21 (Xinhua) -- Expressing concern about the rising number of civilian casualties in Ukraine's Donbas region, Russian President Vladimir Putin discussed the deployment of United Nations (UN) peacekeepers with Ukrainian President Petro Poroshenko in a phone conversation Thursday.

It was the second call in two weeks, according to a Kremlin press release.

The leaders exchanged views on the implementation of the Russian initiative to establish a UN peacekeeping mission in Donbas to protect the truce monitors of the Organization for Security and Co-operation in Europe.

According to a statement released by Poroshenko's press service, the two presidents discussed the deployment in the Normandy format, a diplomatic group comprising Ukraine, Russia, Germany and France.

The Normandy format, also known as the Normandy contact group, was set up to resolve the conflict in Donbas that erupted in April 2014.

The armed confrontation between Ukrainian government troops and pro-independence insurgents in Donbas has claimed about 10,000 lives.

On Sept. 5, 2017, Putin said Moscow would ask the UN Security Council to send peacekeepers to patrol the contact line, which separates Ukrainian and separatist forces in Donbas.

Kiev said it would agree to the deployment of the UN patrol only if the troops were stationed across the whole area controlled by the rebels, including the Ukrainian-Russian border.

In the phone conversation, the presidents also discussed detainee swaps and visits by human rights commissioners from both countries.

Ukraine accuses Russia of aiding the insurgents and sending troops to combat areas in Donbas. Moscow has repeatedly rejected the accusation.

The Normandy contact group signed an agreement in February 2015, envisaging a cease-fire, a withdrawal of heavy weaponry from the contact line, prisoner exchanges and elections in Donbas.

But the deal was never fully implemented, with Kiev and the insurgents accusing each other of breaching the truce.