President Donald Trump has formally designated Saudi Arabia as a Major Non-NATO Ally of the United States, marking a significant enhancement of the longstanding strategic partnership between the two countries.

The announcement came during a state visit by Crown Prince Mohammed bin Salman to Washington, where the leaders signed a comprehensive Strategic Defence Agreement designed to deepen military cooperation and expand joint capabilities.

In remarks at a White House gala dinner honoring the crown prince, Mr. Trump described the move as a step to “take our military cooperation to even greater heights,” adding that the designation was ‘‘very important’’ to Riyadh.

Under US law, Major Non-NATO Ally status confers certain benefits in defence trade, security cooperation and joint research while stopping short of formal collective defence commitments associated with NATO.

Mr. Trump said the enhanced partnership would support shared security interests in the Middle East and globally, with Riyadh positioned as a key defence collaborator.

The designation accompanies a package of defence and economic agreements signed during the visit, including approvals in principle for future US sales of advanced military equipment and plans for almost three hundred American tanks.

The Strategic Defence Agreement also aims to facilitate defense industrial cooperation, technology transfer and burden-sharing arrangements that US officials say will strengthen deterrence and readiness in the region.

Crown Prince Mohammed bin Salman highlighted the longstanding history of US–Saudi cooperation and said the agreements opened a ‘‘new chapter’’ for bilateral relations spanning defence, energy and economic investment.

The announcement builds on Trump’s broader policy of expanding US security partnerships across the Middle East and reflects Riyadh’s deepening ties with Washington as part of Saudi efforts to modernize its military and diversify its strategic relationships.

While Major Non-NATO Ally status does not substitute for formal treaty obligations, analysts say it enhances interoperability, simplifies defence trade and signals a mutual commitment to addressing shared challenges.

Leaders from both capitals have framed the move as an enduring foundation for cooperation on regional stability, counter-terrorism and emerging security technologies.