Salman bin Abdulaziz
© ReutersSaudi Arabia's King Salman bin Abdulaziz
Saudi Arabia's King Salman has approved the hosting of U.S. troops for the first time since Iraqi dictator Saddam Hussein was toppled in 2003, as the two allies bolster cooperation amid rising tensions with Iran.

A Defense Ministry spokesman was quoted by Saudi state news agency SPA as saying on July 19:
"Based on mutual cooperation between Saudi Arabia and the United States of America, and their desire to enhance everything that could preserve the security of the region and its stability...King Salman gave his approval to host American forces."
Saudi officials provided only limited details about the agreement. But senior U.S. defense officials told AP that some troops and Patriot air-defense missile systems had already arrived at Prince Sultan Air Base, south of Riyadh and site of the previous U.S. deployment. Troops are preparing the base for the arrival of aircraft and additional soldiers later in the summer, one U.S. official said.

U.S. Central Command said in a statement on July 19 that the "movement of forces provides an additional deterrent, and ensures our ability to defend our forces and interests in the region from emergent, credible threats."

The United States already has several bases in the region and has troops stationed on the territory of many Arab allies, including Qatar, Bahrain, and the United Arab Emirates.

Sunni Muslim Saudi Arabia is a close U.S. ally and a bitter rival of Shi'ite-led Iran. Washington considers the Saudis to be a powerful counterweight to Iran's influence in the region.

The U.S. military presence in Saudi Arabia lasted 12 years, beginning with Operation Desert Storm in 1991, in which a U.S.-led coalition reversed Iraq's invasion of Kuwait.

Tensions have soared between Washington and Tehran since U.S. President Donald Trump pulled out of the 2015 nuclear accord that Iran signed with six world powers. Trump reimposed crippling sanctions on Iran that had been lifted under the deal in return for curbs on Tehran's nuclear program.

Tensions have ratcheted up in recent weeks -- nearly leading to armed conflict -- over a spate of dangerous incidents off the Iranian coast in the Strait of Hormuz, one world's most strategic commercial shipping routes.

Iran on July 19 seized a British-operated oil tanker in the strait and briefly detained another in an apparent retaliation for a seizure off Gibraltar -- a British territory -- of an Iranian tanker on July 4.

Washington on July 19 said it had shot down an Iranian drone that was menacing a U.S. warship in the Strait of Hormuz, while Tehran denied that it had lost such a craft.