Iran said the United States has violated a ceasefire after the US conducted what it called defensive strikes in southern Iran, while US Secretary of State Marco Rubio said negotiating a deal to halt the conflict could "take a few days".
Iran's foreign ministry said US strikes in Iran's southern Hormozgan province, where Iranian media reported sounds of explosions early on Tuesday, represented a "gross violation" of a tenuous ceasefire in place for nearly seven weeks.
Both sides had previously indicated progress on a memorandum of understanding that could halt the war and restart shipping through the blockaded Strait of Hormuz, while giving negotiators 60 days to tackle more complex issues including Iran's nuclear program.