MOSCOW, September 1, 2018 (News Wires) - The murder of east Ukraine's main separatist leader is a provocation that will undermine a Western-brokered peace agreement, Russian President Vladimir Putin's spokesman said on Saturday. "This is no doubt a provocation," Kremlin spokesman Dmitry Peskov told reporters, Russian news agencies reported. "Alexander Zakharchenko's death will certainly lead to increased tensions in the region" and undermine the so-called Minsk agreements brokered by France and Germany in 2015. In a related development, Foreign Minister Sergei Lavrov said on Saturday that the talks on Ukraine with leaders from Russia, Ukraine, France and Germany, known as the Normandy format, were impossible after Zakharchenko's killing. "It is impossible to talks about upcoming meetings in the Normandy format as many of our European partners wanted," Sergei Lavrov told reporters. "This is a serious situation that needs to be analysed," Lavrov said, referring to the killing of Zakharchenko, leader of Russian-backed separatists in the Donetsk region of eastern Ukraine who died in an explosion on Friday.