Shiite rebels who recently overran Yemen’s capital on Tuesday seized control of a key port city on the Red Sea and a province south of Sanaa in a stunning new blitz that is certain to deepen the country’s turmoil, security and military officials said.

The land grab indicates the rebels, also known as the Houthis, may be determined to carve out a mini-state within Yemen, taking advantage of the weakness of the central government and the disarray in the army and security forces.

The Shiite rebels’ offensive is the latest chapter in the chaos prevailing across much of this impoverished country on the southern tip of the Arabian Peninsula. […]