India, Feb. 25 -- US President Donald Trump issued a sharp warning to Iran during his State of the Union Address on Tuesday local time, making it clear that while diplomacy remains his preferred route, Washington will not permit Tehran to acquire nuclear weapons.

"My preference is to solve this problem through diplomacy-but one thing is certain: I will NEVER allow the world's number one sponsor of terror, which they are, by far, to have a nuclear weapon," Trump said, striking a forceful tone even as he left the door open for negotiations.

In his address, Trump accused Tehran of resuming efforts to advance its nuclear and missile capabilities. He said Iran is "again pursuing their sinister ambitions," and warned that the threat now exten...