Ukrainian President Petro Poroshenko has proposed instituting a unilateral cease-fire in eastern Ukraine as part of a peace plan to address months of conflict in the region.
Russian news agencies quoted Poroshenko on Wednesday as saying the cease-fire would give separatist fighters the opportunity to disarm and those who want to leave the country a chance to get out.
His comments come a day after he discussed a possible cease-fire in a telephone call with Russian President Vladimir Putin.
Their conversation was only the second known direct contact between leaders of the two countries since Russia annexed Ukraine's Crimean Peninsula in March. Pro-Russian separatists have since mounted a rebellion in Ukraine's east, and Moscow has cut off natural gas supplies to its neighbor over unpaid gas debt.
Meanwhile, the Office of the U.N. High Commissioner for Human Rights accused the pro-Russian separatists in eastern Ukraine of creating a climate of insecurity that is ruining their own region. In a new report, the office says the human rights situation has deteriorated significantly in the regions of Donetsk and Luhansk, where the rebels have declared so-called "people's republics."
A U.N. human rights official, Gianni Magazzeni, said Wednesday that armed groups in those areas have created "a reign of fear if not a reign of terror."
Meanwhile, Ukrainian Interior Minister Arsen Avakov said Wednesday that officials believe an explosive device was responsible for a blast at a pipeline carrying Russian gas to the rest of Europe.
Prime Minister Arseniy Yatsenyuk called Wednesday's explosion "sabotage" that he said was designed to undermine Ukraine's reputation as a reliable partner in transferring energy.
"That's why it's absolutely clear who is interested in damaging trust in Ukraine's gas transport system. Ukraine declares that it is a reliable transit country, we carried out and will carry out all our obligations in the sphere of transporting natural gas," said Yatsenyuk.
The blast, about 200 kilometers east of Kyiv, came as Moscow and Kyiv face a stalemate over natural gas pricing that led Moscow on Monday to cut supplies to its neighbor. Analysts say an extended cutoff could interfere with gas deliveries across a wide area of Eastern Europe and beyond.
Pro-Russian troops prepare to travel in a tank on a road near the town of Yanakiyevo, Donetsk region, eastern Ukraine, June 20, 2014.
People carry their belongings as they walk to cross the border into Russia at the Ukrainian-Russian border checkpoint in Izvaryne, eastern Ukraine, June 20, 2014.
A man examines a destroyed building after fighting between Ukrainian and pro-Russian fighters in the city of Artyomovsk, Donetsk region, eastern Ukraine, June 20, 2014.
Pro-Russian fighters wave a white flag to start a handover of the bodies of Ukrainian troops killed in a plane shot down near Luhansk, at a check point in the village of Karlivka near Donetsk, eastern Ukraine, June 18, 2014.
Pro-Russian fighters wait for representatives of the Ukrainian troops at a checkpoint in the village of Karlivka for the handover of the bodies of Ukrainian troops who died in a plane shot down near Luhansk, Ukraine, June 18, 2014.
Pro-Russian separatists stand guard at a check-point as a car drives past outside Luhansk, Ukraine, June 18, 2014.
Miners, one of them carrying a sign with the name of the mine Trudovskaya, march in support of peace in Donetsk, eastern Ukraine, June 18, 2014.
Residents collect water at a pumping station in the eastern Ukranian city of Slovyansk, June 17, 2014.
A woman walks past portraits of protesters who were killed in clashes with police in February in Independence Square in Kyiv, June 18, 2014.
People take part in a rally to press demands for parliament to be dissolved and early elections outside the assembly in Kyiv, June 17, 2014.
Pro-Russian fighters walk past remnants of a downed Ukrainian army aircraft Il-76 at the airport near Luhansk, Ukraine, June 14, 2014.