US gasoline futures climbed above $3.40 per gallon, ending a two-day decline, as fading hopes for a diplomatic Middle East resolution and possible US diesel export restrictions heightened concerns about fuel availability. President Donald Trump rejected Iran’s conditional proposal to reopen the Strait of Hormuz, a strategic waterway between the Persian Gulf and Gulf of Oman, increasing expectations of an extended disruption, though he said negotiations could resume this week. Trump also said he was considering a US diesel export ban "very seriously" and warned it could push gasoline prices higher. Such a ban could lead refiners to reduce crude processing and gasoline output, further tightening domestic supply. Energy Secretary Chris Wright said the administration was seeking voluntary export reductions from refiners, while industry groups called for suspending the federal diesel tax instead.