“They are not sure that surely the Muscovites and those from St. Petersburg, Yekaterinburg and elsewhere will be ready to do it.” Officials said the West also does not expect the worst of the Russian economic blow to arrive until the fall as sanctions, such as oil embargoes, begin to bite. Speculation of a mass mobilization has swirled since the start of the war, but Mr Putin has resisted the urge to send civilians into battle, even as the Russian military struggles to gain ground. British intelligence last month estimated that 55 percent of Russian-backed separatist forces in Donetsk had perished, calling losses in Donbas “extreme.” Morale in the Russian military is said to be low, and recruits reportedly receive only three to seven days of training before being sent into battle. The State Department said on Monday that the depletion is also likely to hurt Russian military advances. He said: “The lack of scheduled breaks from intense combat conditions is quite possibly one of the most damaging of the many personnel issues that the Russian Foreign Ministry is struggling to correct among the deploying force.” The Kremlin expected to take control of key cities in Ukraine within days, but Russia has faced stiff resistance from the Ukrainian military, which has been bolstered by equipment and money from the West. A series of military setbacks have forced the Kremlin to refocus its efforts on eastern Ukraine, but progress has been slow despite the capture of the city of Luhansk.