Vice President JD Vance told reporters that "we have not reached an agreement" following face-to-face talks with Iranian leaders and Pakistani negotiators.
Partial official results show opposition leader Peter Magyar's party dominating the vote, in a bombshell election result with repercussions around Europe and beyond.
The incident took place at the Citadelle Henri, also known as Citadelle Laferriere, a 19th-century fortress and tourist spot in the northern town of Milot.
President Trump said the U.S. Navy will begin blockading ships from entering or exiting the Strait of Hormuz and intercept vessels that have paid tolls to Iran.
