Tehran, Sept. 4 -- Iranian officials ratcheted up pressure Wednesday ahead of a weekend nuclear deadline for European nations to come up with a solution for Iran to sell its oil abroad in the aftermath of escalated U.S. sanctions.

President Hassan Rouhani reiterated a threat that Tehran would take additional steps away from the 2015 nuclear accord on Friday and accelerate nuclear activities if Europe fails to provide a solution, calling it Iran's third, "most important step" away from the deal.

"Iran's third step is of an extraordinarily significant nature," Rouhani said, without detailing what it would entail, but saying a "decree will be announced today or tomorrow."

Meanwhile, Iran's foreign ministry announced that seven members of ...