Diesel prices in the U.S. have hit a painful new milestone, $6 a gallon as, reports said, Houthi rebels in Yemen took the key Red Sea port city of Mokha.

A Red Sea crisis deepens as the Saudi East-West pipeline is shut down and the Houthis grab effective control of the strategic Bab al-Mandeb Strait.

Perim Island sits in the Bab al- Mandeb Strait, a globally important maritime chokepoint at the mouth of the Red Sea.

Almost three years after the Houthis first garnered international attention by attacking ships off Yemen, the rebels have only increased their violent influence in the Middle East. Here's a primer on the group that could push the price of global oil even higher.