Mexican stocks plunged 4.87 percent on Friday, despite the country being left off US President Donald Trump's reciprocal tariffs list, amid panic on global markets over the start of a trade war.

Argentine stocks also took a battering, falling more than seven percent in Friday trading, two days after Trump imposed sweeping import duties on dozens of nations including Argentina.

The Mexican rout came despite stocks ending marginally up on Thursday, by 0.54 percent, reflecting initial relief in Latin America's second-biggest economy at having dodged Trump's so-called "Liberation Day" tariffs.

If Mexico was spared, Latin America's biggest economy Brazil, and Argentina, the third-largest, were not.

Argentina's flagship Merval Index fell 7.38 percent while Brazil's Bovespa Index lost 2.96 percent.

Both countries were hit with 10 percent tariffs, like much of Latin America — at the lower end of a spectrum ranging upwards to 50 percent.