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.”

The Pentagon said on Wednesday that U.S. strikes 10 days ago had degraded Iran's nuclear program by up to two years, suggesting the U.S. military operation likely achieved its goals despite a far more cautious initial assessment that leaked to the public.