(ANSA-AFP) - KYIV, SEP 23 - Moscow-held regions of Ukraine began voting Friday on whether to become part of Russia, in referendums that Kyiv and its allies have condemned as an unlawful land grab. The referendums in eastern Donetsk and Lugansk regions, as well as in the southern Kherson and Zaporizhzhia regions have been roundly dismissed as a sham by Kyiv's Western allies. They come after Putin announced this week a mandatory troop call-up for about 300,000 reservists, which also sparked resounding condemnation in the West. The mobilisation comes after Ukrainian forces seized back most of the northeastern Kharkiv region in a huge counter-offensive that has seen Kyiv retaking hundreds of towns and villages under Russian control for months. The four regions' integration into Russia -- which for most observers is already a foregone conclusion -- would represent a major new escalation of the conflict. "We cannot -- we will not -- allow President Putin to get away with it," US Secretary of State Antony Blinken said in a UN Security Council session on Thursday, lashing out against the referendums as a "sham". (ANSA-AFP).