(ANSA) - BELGRADE, MAY 18 - To overcome Ukrainian resistance, Russia has made significant use of auxiliary personnel and "this includes a deployment of Chechen forces, likely consisting of several thousand fighters primarily concentrated in the Mariupol and Luhansk sectors," the UK Ministry of Defence said in its latest intelligence update today. "These forces likely consist of both individual volunteers and National Guard units, which are routinely dedicated to securing the rule of Chechen Republic Head, Ramazan Kadyrov," the report reads. However, "the combat deployment of such disparate personnel demonstrates Russia's significant resourcing problems in Ukraine and is likely contributing to a disunited command which continues to hamper Russia's operations." (ANSA).