With one American carrier strike group already in the Middle East and another apparently on its way as U.S. President Donald Trump ramps up pressure on Iran to give up its nuclear program, fears are rising of the outbreak of another war that could spread into a regional conflict.

The 12-day Israel-Iran war last year appeared to cripple key elements of Iran's military, yet left its capabilities far from neutralized — a distinction that looms large as tensions rise again.