Nearly 150,000 residents of separatist-controlled eastern Ukraine with Russian passports will join Russians in voting on a set of constitutional reforms that would allow President Vladimir Putin to extend his rule, a Russian official has said.

From June 25 to July 1, Russians will vote on the constitutional amendments, which contain a controversial clause to “zero out” Putin’s presidential term limit, allowing him to run for two more six-year terms.

Residents of the eastern Donbass region who hold Russian passports will be able to easily cross the border to cast their ballots, State Duma deputy Viktor Vodolatsky told the state-run TASS news agency Wednesday.

“Today, more than 150,000 citizens [in the Donbass] already want to vote on the amendments to the Constitution. … There’s no difficulty in crossing the border for a Russian citizen,” said Vodolatsky, the First Deputy Chair of the Duma’s CIS Affairs and Relations With Russian Nationals Abroad Committee.

Vodolatsky added that while Donbass residents are required to vote on Russian territory, other Russian citizens living abroad can cast their ballots at the nearest consulate.

Moscow says it has issued Russian citizenship to over 196,000 residents of the Donbass region and neighboring areas of eastern Ukraine that are under Kiev’s control since Putin simplified the procedure last year. 

Despite a ceasefire signed in 2015, more than 13,000 people have been killed in six years of bitter war between Ukrainian troops and pro-Russian separatists in the Donbass.

Western countries accuse Russia of providing troops, equipment and funding to the separatists and have sanctioned Moscow over its role in the conflict.