US President Donald Trump accused Iran on Wednesday of taking too long to negotiate a peace deal and warned it would now "have to pay the price", a day after suggesting an agreement was in the offing.
The remarks came after Iran and the US once again traded fire following the downing of an American helicopter, further straining a ceasefire that took effect in April but has been marked by sporadic flare-ups of violence.
The exchange drew international calls for restraint on the eve of the World Cup, which the US is co-hosting and Iran is participating in.