WASHINGTON, United States (AFP) — United States (US) President Donald Trump lashed out at critics of his agreement with Iran on Thursday, calling those who accused him of offering concessions to end the war "fools", ahead of negotiations in Switzerland on implementing the deal. Oil prices tumbled after Trump and his Iranian counterpart separately signed their accord to end the Middle East war, with the Strait of Hormuz to reopen but two months of negotiations lying ahead. In a sudden development after uncertainty over when the deal agreed earlier this week would be formally signed, Trump put his name to it in thick black ink at a candlelit dinner with French President Emmanuel Macron at the Palace of Versailles outside Paris on Wednesday.