Mexico's peso fell for a fourth consecutive session on Tuesday and briefly touched the 21-per-dollar level for the first time in a month after the United States imposed 25% tariffs on imports from Mexico.

The Mexican peso has reversed earlier losses, joining a broader rally across emerging market currencies, as traders weigh whether US levies against some of its key trading partners will prove short-lived.

President Claudia Sheinbaum said that Mexico could shift trade alliances "if necessary," referring to the possible continuation of the tariffs.