The short answer is no. They tried to do that in the first half of 2014 and they lost. The Ukrainian forces were on the verge of taking back all of Donbass in August when the regular Russian Red Army went in and defeated Ukraine at Ilovaisk in early September. So the mask came off at Ilovaisk. But they do not have the ability to do that, and that surprised them.
On November 6th, 2018. See this statement in context.