BRUSSELS — Three former NATO secretaries general have called for the alliance’s new $1.4 billion Brussels-based headquarters to be named after the late U.S. Sen. John McCain, who died Aug. 25 after battling brain cancer.

In a letter, Anders Fogh Rasmussen (who served in the top post from 2009-2014), George Robertson (1999-2003) and Javier Solana (1995-1999) have supported the tribute to the Arizona Republican’s work in “promoting transatlantic unity.”

The letter, published Thursday, reads: “As three former secretary-generals of Nato, we believe that the transatlantic alliance is the cornerstone of a stable, peaceful and free world. Few things symbolise this alliance, and the enduring benefits of American global leadership, more vividly than the life and work of John McCain.

"Despite his being a US Senator, across Europe we all felt that John McCain III was one of our own. Whether advancing the cause of freedom across the former Soviet states of eastern Europe or defending the multilateral international order at a time of scepticism, his work was a beacon for all of us who believe that transatlantic unity is the only means of ensuring peace.

"We urge Nato to repay this lifetime of service to its mission by naming its new Brussels headquarters after Senator McCain."

McCain, a two-time U.S. presidential candidate and Vietnam veteran, died at the age of 81. He was a regular visitor to NATO in Brussels and a vocal advocate for the alliance throughout his career.

In contract, U.S. President Donald Trump has been highly critical of the alliance, noting the U.S. spends more on defense spending than other NATO members, and he has threatened to pull out. The two American leaders publicly clashed on a number of issues.

The new NATO headquarters, the political and administrative base for the alliance, opened earlier this year. The huge glass and steel building will eventually house 4,200 staff and 29 embassies.

Rasmussen will travel to Washington for McCain’s memorial service on Sept. 1.

The Norwegian tweeted: “I can think of no more fitting tribute to Senator John McCain than to name the new NATO HQ after him.”

On Thursday, he also told Defense News: “Every person who enters the building should be reminded that our alliance represents the highest ideals of cooperation and multilateralism; ideals the American statesman embodied like few others.

The naming idea is also backed by former Estonian President and former Member of the European Parliament Toomas Hendrik Ilves, who said McCain was one of Estonia’s “biggest friends and supporters.”

Others supporting the call include U.K. Tory Member of Parliament Tom Tugendhat and U.S. Sen. Marco Rubio, R-Fla.

“Secretary General Jens Stoltenberg has noted the proposal to name NATO headquarters after John McCain. This proposal will be studied carefully," a NATO spokesperson said.