The Pentagon on Wednesday sharpened its assessment of Iran's nuclear program, declaring that Iran's ability to build a nuclear weapon following the U.S. strike on its nuclear facilities is "closer to two years" away.

The new assessment contrasted with U.N. agency view that Iran could resume enriching uranium in a “matter of months.”

CIA Director John Ratcliffe has told skeptical U.S. lawmakers that American military strikes destroyed Iran’s lone metal conversion facility and delivered a monumental setback to Tehran’s nuclear program that will take years to overcome.