Amid rising tensions in region, Houthi rebels attack border town's airfield and military base

'Our steps were very prudent,' Acting Defense Secretary Patrick Shanahan says of US deployment of ships, bombers to region amid intelligence warnings of Iranian attack plans

Proposal by Pentagon officials suggests deployment nearing Gulf War levels if Iran were to expedite nuclear program or targets US forces

White House says president will nominate former Boeing executive, who has been acting Pentagon chief since Mattis left job four months ago

Movement of weapons spurred Washington's decision to send aircraft carrier to Middle East, could indicate preparations to attack American forces in the region