Speaking to reporters at the State Department, Rubio said Tehran is seeking to rebuild aspects of its nuclear program despite previous setbacks. "They are not enriching right now,” he said, "but they are working toward the point where they could.” Rubio did not provide intelligence details but asserted there are "reasons to believe” Iran would resume uranium enrichment if given the opportunity.

Rubio emphasized that upcoming negotiations would focus primarily on nuclear constraints, reflecting President Donald Trump’s stated preference for a diplomatic resolution. However, he described Iran’s refusal to discuss its ballistic missile program as "a very big problem.”

According to Rubio, Iran maintains "thousands of short-range ballistic missiles” capable of striking U.S. installations across the Gulf, including bases in Saudi Arabia, Qatar, Bahrain, and the United Arab Emirates. He also cited concerns over Iran’s expanding missile range and satellite launch efforts, which U.S. defense officials have previously warned could contribute to intercontinental ballistic missile development.

The secretary declined to comment directly on a recent Defense Intelligence Agency assessment suggesting Iran could develop missiles capable of reaching the U.S. homeland by 2035 if it chose to pursue that path. "Suffice it to say, it’s a threat, and we see it as possible,” Rubio said, referencing North Korea’s past missile advances as precedent.

Iranian officials have consistently maintained their nuclear program is peaceful and have rejected Western demands to limit missile development, calling it a sovereign defense matter.

Diplomatic engagement remains open, Rubio said, but progress on nuclear limits will likely determine whether broader security issues can be addressed.