MEXICO CITY - Mexico is ready to hold a highly contested state election considered to be a bellwether for the 2018 presidential race, the national electoral institution announced on Thursday.

On Sunday, residents in the central state of Mexico will go to the polls to choose a governor in the most closely watched regional contest in recent years, with both the center-right ruling party and left-leaning opposition viewing the outcome as an indication of their chances in next year's general elections.

Though local elections will also take place in the Gulf Coast state of Veracruz and gubernatorial elections in the northern states of Coahuila and Nayarit, all eyes will be on Mexico State, where the ruling Institutional Revolutionary Party (PRI) had governed Mexico uninterrupted for 90 years.

The PRI stronghold is the country's most populous state and a launch pad to the presidency. Mexico's President Enrique Pena Nieto won the presidency in 2012 after serving as a governor of Mexico State from 2005 to 2011.

"The table has been set to recreate democracy peacefully and with absolute freedom on Sunday, June 4," the president of the National Electoral Institute (INE), Lorenzo Cordova, said at a press conference.

According to political observers, if the opposition National Regeneration Movement (MORENA) wins the state, it would signal the strength of the opposition and the weakening of the PRI.