Officials are preparing to organize votes in areas currently controlled by the Russian military and any others its troops are able to seize in coming weeks, three people said. The goal is to conduct referendums on joining Russia by Sept. 15, two of the people said, asking not to be identified because the issue is sensitive.

The project is directed by Sergei Kiriyenko, the Kremlin’s first deputy chief of staff, according to the people, with attention focused on the Donetsk and Luhansk regions in Ukraine’s east as well as the southern territories of Kherson and Zaporizhzhia. Kiriyenko, who is under US and European Union sanctions, regularly visits occupied territories to oversee officials preparing for the referendums, they said.

With its military struggling to advance in recent months, annexation would give the Kremlin a sign of apparent progress in the operation to show Russians and signal its unwillingness to discuss giving up the territories in any potential future peace talks. Still, it’s far from clear what votes Russia could hold after millions of Ukrainians fled their homes following Putin’s Feb. 24 order to invade, though the Kremlin has years of experience of rigging results in domestic elections.