Mexico’s President Claudia Sheinbaum sought to cool tensions with the United States on Monday after an incident in Chihuahua in which two CIA agents died in an accident, saying the federal government does not want the episode to spiral into a broader confrontation.

Speaking during her morning news briefing, Sheinbaum said Mexico hopes the case remains isolated and that it expects Washington to respect Mexico’s constitution and its national security laws moving forward. “Let us hope this is an exceptional case … and that a situation like this never happens again,” she said, according to the Associated Press.

The controversy surfaced last week amid Mexico’s position that the CIA agents were not authorized to operate in the country. Mexico’s Ministry of Security said Saturday that one of the U.S. agents entered Mexico as a visitor, while the other entered using a diplomatic passport, and it reiterated that it was unaware of foreign agents operating in Mexico.

The episode also intersected with state-level politics in Chihuahua. The head of the Chihuahua state prosecutor’s office, César Jáuregui Moreno, resigned on Monday night after telling reporters days earlier that the state government had worked with U.S. agents on an operation. He later walked back those comments under pressure from Sheinbaum.

In addition to Sheinbaum’s remarks, the AP reported that the two deceased Americans were CIA members, with a U.S. official and two other people familiar with the matter confirming that characterization last week on condition of anonymity because of the sensitivity of intelligence operations. The CIA declined to comment.

Sheinbaum said the details of the operation in Chihuahua must be clarified, and she urged the Attorney General’s Office and other relevant authorities to take action after an upcoming debate in Mexico’s Senate. Chihuahua Gov. María Eugenia Campos, a prominent opposition figure, was called to testify in Mexico City on Tuesday alongside the state attorney César Jáuregui.

The dispute arrives amid long-running scrutiny of U.S. intelligence activity in Mexico. The AP noted that for decades, the CIA and the Drug Enforcement Administration, DEA, presence in Mexico has been marked by controversy, with past flare-ups including 2012 when a U.S. Embassy vehicle was shot at outside Mexico City and two CIA agents were wounded.

Last year, Mexico and the Trump administration reached an agreement to coordinate actions and exchange information regarding security, while respecting the sovereignty of both countries. On Monday, Sheinbaum’s administration framed the Chihuahua incident as something Mexico believes should be treated as exceptional while authorities determine what occurred.