Iran is still believed capable of fielding a long-range ballistic missile that could hit the United States by next year.
"The prediction or the assessment of 2015 remains, from my understanding," the top U.S. nuclear-combat commander said at a Senate Armed Services Committee hearing on Thursday.
Strategic Command head Navy Adm. Cecil Haney said the current estimate tracks with what the top U.S. intelligence official, retired Air Force Lt. Gen. James Clapper, said last year.
However, Haney this week declined to publicly elaborate on the potential threat in response to questions from Senator Kelly Ayotte (R-N.H.), noting that details remain classified.
In an analysis last year, the Defense Department said Iran would require assistance from nations such as China, North Korea or Russia, if Tehran is to meet that estimated date for flight-testing.
The strategic commander's comment came a week after the United States and five other countries concluded their first round of talks with Iran on potentially lifting international sanctions against the Middle Eastern nation in return for long-term restrictions on its nuclear activities. Despite agreeing on an agenda for future negotiations, Washington and Tehran appeared to remain at odds over whether new discussions could examine the possibility of limiting Iran's ballistic-missile operations.
In response to Ayotte's questions, Haney said a proposed East Coast missile-defense site would provide "additional capability" against any Iranian intercontinental ballistic missile threat. However, he added that technical problems with the Ground-based Midcourse Interceptor must still be addressed, as the possible new defensive site would rely on this technology.
"We have to invest in priorities [in] order to work to get our sensing and discrimination right, as well as getting our kill vehicle also performing to spec," he said.