Ethiopians were voting on Monday in a referendum on the creation of a 12th regional state in the south of the country, the third such ballot in under four years.

More than three million people are registered to vote in areas that currently fall in the Southern Nations, Nationalities and Peoples Region (SNNPR), according to election board figures cited by state media.

Results are due on February 15.

Since Prime Minister Abiy Ahmed came to power in 2018, two new regional states have already been carved out: Sidama in 2019 and South West in 2021.

Both separated from the SNNPR, a mosaic of minority ethnic groups and scene of tension and violence in recent years.

Africa's second most populous country has faced several challenges to its unity and stability, including the two-year war in Tigray that ended with a peace deal in November and an ongoing insurgency in the largest region of Oromia.

The current constitution adopted in 1995, four years after the fall of the military-Marxist Derg regime, had initially divided Ethiopia into nine regional states, cut out along ethno-linguistic lines and enjoying considerable power in a federal system.

This "ethnic federalism" was supposed to offer a degree of autonomy to the 80 or so ethnic communities that make up Ethiopia, but has been accused by critics of exacerbating inter-communal tensions.