The self-proclaimed Donetsk People's Republic (DPR) intends to increase the size of the DPR forces supported by the self-proclaimed Luhansk People's Republic (LPR) forces to 100,000 men, DPR leader Alexander Zakharchenko said.

"The joint army of the DPR and the LPR will be 100,000 men strong. Mobilization is the first stage; there will be volunteers at first and we shall see what to do next," he told reporters.

"The recruitment of volunteers will begin already next week," Zakharchenko said.

Fighting has increased in eastern Ukraine in the past few weeks and hopes of easing the situation faded after peace talks collapsed on Saturday.

Kiev has also mobilized more troops because of the surge in fighting.