MEXICO CITY — Authorities in northern Mexico on Wednesday found 32 kilograms of fentanyl hidden inside boxes of sliced cactus, a quintessential Mexican food staple known as nopales.

Mexican law enforcement said they seized some 275,000 pills of the lethal drug in the border state of Sonora, on its way to Arizona, and that they arrested a 29-year-old man. The drugs were valued at about $6.5 million. Authorities found both pills and the drug in powder form.

It’s just the latest in a cat-and-mouse game between drug smugglers and authorities, as traffickers find increasingly outlandish ways to sneak drugs into other countries. Packets of cocaine and fentanyl have been found tucked away in hair extensions and inside avocados, and even transported via submarine.

The seizure also comes during a tense moment between Mexico and the United States, as Mexico scrambles to satisfy President Donald Trump’s demands to stop the flow of fentanyl and migrants north, which he has used to justify the 25% tariffs he put in place on Tuesday, though migration north and fentanyl overdoses had already sharply dipped before Trump took office.

On Wednesday, Trump said that after negotiating with Mexican and Canadian authorities he would grant a one-month tariff exceptions to automakers, offsetting the brunt of the economic blow tariffs would dole out.

The fentanyl seizure happened at a military checkpoint on the Mexican highway connecting the northern states of Sinaloa and Sonora, where officers searched a trailer carrying packets of nopales.