Special Representative of the OSCE's Chairperson-in-Office in Ukraine and in the Trilateral Contact Group (TCG) Ambassador Heidi Grau has said the use of heavy weapons in Donbas undermines confidence between the sides. Read alsoZelensky: Russian escalation possible at any moment up to late SeptemberAccording to Grau, compliance with the ceasefire was in the focus of the discussions of the Working Group on Security Issues and the TCG. What is more, the Economic Working Group focused on water supply issues in certain areas of Donetsk and Luhansk regions of Ukraine (CADLR), especially in the area of activities of the public utility enterprise "Voda Donbassa."