World Trade Organization (WTO) Director-General Roberto Azevedo on Monday warned of the potential "domino effect" of proposed U.S. tariffs on steel and aluminum.
Azevedo, who was in Brazil to attend the upcoming World Economic Forum for Latin America, said "this escalation, which I say has a domino effect, is an escalation that is tough to reverse."
"Once you enter the path of reciprocal reprisals, you know when it begins, you know how it begins, but you don't know how or when you will be able to stop the process," Azevedo told reporters.
The Brazilian-born WTO chief met with Brazilian President Michel Temer in Brasilia to discuss the U.S. decision to slap steep tariffs on imported steel and aluminum.
U.S. President Donald Trump last week formally signed proclamations to impose a 25-percent tariff on imported steel and a 10-percent tariff on aluminum, causing mounting dissent among business groups and trading partners around the world.
Brazil, the second-largest exporter of steel to the United States, joined the protest against the protectionist measure.
"Unilateral" announcements like those made by Trump tend to spark counter measures, said Azevedo.
"This process of action and reaction lead, sometimes, to trade wars that are not in anyone's interest, where there are only losers, since there are no winners in a trade war," he warned.