(NewsNation) — Mexican President Andrés Manuel López Obrador has come out in favor of negotiating a peace agreement with his country’s powerful drug cartels.

The Mexican leader was responding to an open letter from a Mexican activist whose brother is missing. The activist was calling on leaders of the drug cartels to end the practice of forced disappearances.

“I agree and I hope we achieve peace — that’s what we all want,” the Mexican president said about the letter during a press conference. “Violence is irrational, and we’re going to continue looking for peace, to achieve peace, and that is what we’re doing. And if there is an initiative of this kind, of course we support it.”

“Essentially, the goal is to stop this staggering level of violence that we’ve seen, and we’ve seen increase under his administration,” NewsNation Washington correspondent Evan Lambert explained during an appearance on “NewsNation Now.”

The Mexican president’s statement comes as there are increasing calls by politicians in the U.S. for a tougher stance against the drug cartels. Some members of Congress want the cartels to be treated as terrorist organizations, citing the flow of drugs that are killing Americans.

Delia Icela Quiroa Flores Valdez says her brother was kidnapped nine years ago and urged López Obrador in a letter to do more to stop the cartel violence.

“The only thing we want is (to) find our families (who) disappeared,” she told NewsNation.

Amid the ongoing violence, relatives of Mexico’s thousands of missing people are protesting in Mexico City, demanding justice. According to government figures, more than 40,000 people have gone missing since López Obrador took office.

The Mexican president did not elaborate on what sort of deal might be possible, but Quiroa was skeptical it would come to fruition.