Houthi rebels effectively completed a rapid push to take control of Yemenโ€™s Red Sea coastline on Friday, tightening their grip on one of the worldโ€™s most important shipping routes and delivering a dramatic boost to their backers in Iran.

At the same time, strikes inside Saudi Arabia forced the shutdown of a critical oil pipeline, the countryโ€™s energy ministry confirmed Friday.

Saudi Arabia said drones launched from Iraq attacked its East-West pipeline, but said it would not retaliate for now following a request from Iraqโ€™s prime minister, while reserving the right to take all necessary measures to protect its sovereignty, security and critical facilities, according to a Saudi foreign ministry statement.

An Iraqi military commander was dismissed early on Saturday after investigations confirmed the latest drone attacks targeting Saudi Arabia originated from Iraq, according to a statement by Iraqโ€˜s prime ministerโ€™s office.

Houthi forces captured Perim, an island in the middle of the vital Bab el Mandeb Strait, several news agencies reported, citing multiple sources. A day earlier, the Houthis captured the historic port city of Mocha.

That was followed by an advance on the strategic coastal town of Dhubab and the apparent withdrawal of forces from the Saudi-backed, internationally recognized Yemeni government, from Perim, also known as Mayun.

The U.S. military is helping its Saudi counterparts to develop and coordinate targets inside Yemen, according to a U.S. official and a person familiar with the matter, after Saudi Arabia vowed a firm response to hostilities.

The Houthis and the opposing coalition have been fighting a civil war since 2014. The conflict has simmered for years but erupted into intense fighting again in recent weeks, raising concerns of a return to all-out war and posing a serious new threat to the global economy.

Effective Houthi control over Bab el Mandeb, a gateway to the Red Sea trade route that links Europe and Asia, could further imperil oil exports while granting Iran powerful new leverage in its war with the United States.

Saudi Arabia, the worldโ€™s biggest oil exporter, has had to rely on the Red Sea route given the disruption to the Strait of Hormuz, through which some 20% of the worldโ€™s oil used to pass, since the U.S. and Israel waged war on the Islamic Republic in late February.

If the Houthis are similarly able to threaten shipping along the Bab el Mandeb Strait, it could reduce oil supplies through another key waterway and deepen the worldโ€™s energy crisis.