ERBIL, Iraq, Sept. 25 (Xinhua) -- The Iraqi Kurds on Monday cast their votes in a referendum that will determine the independence of the Kurdish region and the disputed areas that are currently under de facto Kurdish control.

About 5.2 million eligible voters in the three northern provinces -- Erbil, Sulaimaniyah and Dohuk -- and other areas outside the region, known as the disputed areas, are expected to cast their votes in 12,000 ballot boxes in 2,000 polling centers across the Kurdish region and the disputed areas.

The voters are to choose either "Yes" to independence Kurdish state or "No" to remain as autonomous region part of the Iraqi state.

The regional electoral committee announced earlier that the voting is to start at 8:00 a.m. (0500 GMT) and end at 6:00 p.m. (1500 GMT).

The Iraqi government has repeatedly rejected the referendum and its results, describing it as "unconstitutional."

"Taking a decision unilaterally that would affect Iraq's unity and making separation from one side is contrary to the law and unconstitutional and we will not deal with it or with its results," Prime Minister Haider al-Abadi the day before said in a statement.

On June 7, the Kurdish regional President Masoud Barzani announced his intention to hold a referendum on the independence of the Kurdish region from Iraq on Sept. 25.

The independence of Kurdistan is opposed by many countries because it would threaten the integrity of Iraq and because it could undermare fight against Islamic State militants.

In addition, neighboring countries such as Turkey, Iran and Syria see that such a step would threaten their territorial integrity, as larger populations of Kurds live in those countries.