Tajikistan is holding a referendum on changing the Constitution to allow its authoritarian president to run for the office indefinitely, effectively allowing him to rule for life.

The 63-year-old President Emomali Rakhmon has ruled the former Soviet republic in Central Asia since 1992. During those 24 years in power, he has crushed or cowed all opposition to his rule and the referendum is expected to pass easily.

By mid-afternoon Sunday, the official turnout for the referendum was about 80 percent.

One of the constitutional changes considered in the vote would lower the minimum age for presidents from 35 to 30 years. This would allow Rakhmon's son, now 29, to run in the next presidential election in 2020 and succeed him as leader of the country.