Meanwhile, there have been warnings that ships could be targeted in regional waters over the tensions.
Al-Busaidi made the announcement on the social platform X.
“I am pleased to confirm the 6th round of Iran US talks will be held in Muscat this Sunday the 15th,” he wrote.
Iran for days had been saying there would be talks, but Oman, which is serving as the mediator, had not confirmed them until now.
U.S. Mideast envoy Steve Witkoff will attend the talks.
“Discussions are expected to be both direct and indirect, as in previous rounds,” said a person familiary with Witkoff's travels, who spoke on condition of anonymity to discuss the upcoming trip.
Reaching a deal is one of the several diplomatic priorities being juggled by U.S. President Donald Trump and his trusted friend and Witkoff. An accord could see the U.S. lift some of its crushing economic sanctions on Iran in exchange for it drastically limiting or ending its enrichment of uranium.
But a failure to get a deal could see tensions further spike in a Middle East on edge over the Israel-Hamas war in the Gaza Strip.
Iran's economy, long ailing, could enter a free fall that could worsen the simmering unrest at home. Israel or the U.S. might carry out long-threatened airstrikes targeting Iranian nuclear facilities. And Tehran may decide to fully end its cooperation with the United Nations' nuclear watchdog and rush toward a bomb.
Iran and the U.S. have held previous talks in Muscat and Rome.
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Associated Press writer Matthew Lee in Washington contributed to this report.