Mexico’s president and the U.S. attorney general have met behind closed doors about a week after U.S. President Donald Trump suggested his government could classify Mexican cartels as terrorist organizations.

Andrés Manuel López Obrador tweeted a photo of himself conversing with William Barr on Thursday in Mexico City.

López Obrador said that “as a lawyer, (Barr) understands that our Constitution obliges us to stick to principles of cooperation for development and non-intervention in foreign policy.”

López Obrador said earlier that he would be accompanied by his security cabinet and Foreign Relations Secretary Marcelo Ebrard.

The encounter was not open to journalists.

A foreign terror organization designation by the U.S. government would mean it views cartels the same as groups such as the Islamic State and al-Qaida.