BRUSSELS (AP) — A landmark free trade deal between the European Union and four South American countries will begin on May 1 after more than a quarter-century of negotiations and new global economic uncertainty unleashed by tariffs, critical mineral controls and the war in Iran. The European Commission said Monday that the start date for the EU-Mercosur free trade deal was triggered by Brussels receiving a “note verbale” from Paraguay that it had approved the deal, which is a key part of the 27-