The government of the northern Mexican state of Coahuila, under investigation for a 9,800 percent increase in its debt since 2005, plans to keep its 2010 financial data secret until 2019, capital daily Reforma said Wednesday.

The newspaper filed an official request for information on Coahuila's public accounts in 2010, when the state was led by Humberto Moreira, now national chairman of the main opposition Institutional Revolutionary Party, or PRI.

The Coahuila auditor general's office responded by telling the daily that last year's financial data will remain secret until 2019.

Humberto Moreira left the governor's office in January to take the reins of the PRI.

He was succeeded on an interim basis by Jorge Torres Lopez, who is due to hand over power Thursday to the new elected governor, Ruben Moreira Valdas, Humberto's brother.

The state's total indebtedness rose from 323 million pesos ($24 million) in 2005 to 7.92 billion pesos ($609 million) in March of this year, and then quadrupled to 32 billion pesos ($2.46 billion) in August.

A third of Coahuila's debt is in the form of short-term obligations.

Rating agency Standard & Poor's downgraded Coahuila's debt five levels, noting that the state's obligations were equal to 260 percent of total 2011 revenues.

The Mexican Attorney General's Office announced earlier this month that it was investigating loans obtained by the Coahuila state government.

The probe was spurred by a report from the federal finance ministry about "irregular" borrowing by the Coahuila administration, the AG's office said.

Coahuila's former treasurer, Javier Villarreal, is already facing charges of fraud and falsifying documents in connection with a total of 3 billion pesos ($222 million) in bank loans to the state.

Political analysts say the AG's office is seeking to incriminate Humberto Moreira as a way of discrediting the PRI ahead of the 2012 general elections.

Mexico is currently governed by the conservative National Action Party, which ended 71 years of PRI rule with its victory in the 2000 presidential election.

But the PRI, led by charismatic former Mexico state Gov. Enrique Peña Nieto, is now widely expected to reclaim the presidency in next year's balloting.