The United Arab Emirates (UAE) continues to top the list of Middle East lobbying spenders as it seeks to consolidate its status as one of America’s closest strategic allies in the region.

The Gulf nation spent $13.5 million last year — on par with 2014 — on an array of influence peddlers and public relations experts, according to a review of financial disclosures. The spending spree has helped the country cement its military partnership with the United States while heading off US-based threats to its world-beating airline industry.

The strength of the bilateral relationship was very publicly confirmed this month when the Barack Obama administration announced the transfer of 15 detainees from the Guantanamo Bay prison in Cuba to the UAE. That’s the largest single transfer to date as Obama races to empty the controversial prison before his term is up despite fierce Republican opposition in Congress.

“The United States is grateful to the government of the United Arab Emirates for its humanitarian gesture and willingness to support ongoing US efforts to close the Guantanamo Bay detention facility,” the US Department of Defense said in an Aug. 15 statement announcing the transfers. “The United States coordinated with the government of the United Arab Emirates to ensure these transfers took place consistent with appropriate security and humane treatment measures.”