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.

"This is the first day that Iran really started winning the war," a Yemeni official said of Houthi territorial gains that give Tehran leverage over a second major waterway.

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.

Saudi Crown Prince Mohammed bin Salman has personally pressed President Trump to take military action against the Iran-backed Houthis, sources tell CBS News.

The Trump administration is offering significant intelligence and targeting assistance to Saudi Arabia but does not currently plan on launching direct military attacks against the Houthis, two U.S. officials told ABC News.

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.