MEXICO CITY — Mexico's President-elect Andres Manuel Lopez Obrador said Wednesday he will put the question of creating a national guard to a referendum conducted by the National Flectoral Institute.

The proposal aimed at confronting the country's violence would require a constitutional reform, meaning that it would need congressional approval and a green light from state legislatures.

"We're going to do both things," Lopez Obrador said, referring to the referendum and constitutional reform.

The president-elect made the announcement to radio journalist Carmen Aristegui during a wide-ranging interview 10 days before he takes office.

A day prior, a coalition of civil society groups and intellectuals signed a letter rejecting the idea of a national guard under command of the military.

Mexico has faced international criticism for leaning heavily on the army and navy to wage the drug war. Numerous human rights violations have been blamed on the military for actions conducted in the name of security.

Lopez Obrador has been among those calling for demilitarization, but said he had not fully realized how hopelessly corrupt civilian law enforcement agencies were.

He also defended the armed forces, saying that the military's infamous human rights violations were "on the orders received from civilian authorities" and that its leaders had good backgrounds.

Lopez Obrador said he had looked at nearly three dozen active generals and found that some were the sons of farmworkers and mechanics. "The chiefs of the armed forces are not part of the oligarchy," he said.

The populist said he decided to create a national guard because he didn't see relying on the police alone as an option.

A national guard would include military police and some federal police.

A separate referendum is already scheduled for this weekend. That one will be conducted by a private foundation and will include questions on a number of Lopez Obrador's proposals.

One of those is related to a proposed train line on the Yucatan Peninsula. Scientists and other academics have expressed environmental fears and called for Lopez Obrador to not take the train question to the public.

But Lopez Obrador has dismissed their concerns, saying they were uninformed.

"Some probably haven't even been to the southeast," he said.

He said half the train would travel on existing rail lines and follow highways or rights of way for electrical transmission lines. He said not a single tree would be felled for the so-called "Mayan train."

Another referendum last month resulted in the cancellation of Mexico City's $13 billion airport project.

"The country has already changed; the citizens count too now, those on the bottom, not just the elites anymore," Lopez Obrador said.