That military tribute you saw at your last pro ballgame — a service member's stirring rendition of "America The Beautiful," a surprise "welcome home" celebration for returning troops, a soldier's ceremonial first pitch — may not have been a charitable gesture by the home team.

Instead, that event may have been paid for by the Pentagon, part of a multimillion-dollar program to promote the armed services and boost recruitment through patriotic events, game tickets, player appearances and other perks.

That initiative was detailed in a Senate report released Wednesday that described the spending as "inappropriate and frivolous" and criticized the Department of Defense for failing to disclose and keep track of such deals.

"Americans deserve the ability to assume that tributes for our men and women in military uniform are genuine displays of national pride, which many are, rather than taxpayer-funded DOD marketing gimmicks," Sens. John McCain and Jeff Flake, the report's co-authors, wrote.

The paid marketing campaigns cast "an unfortunate shadow" over "genuine patriotic partnerships" between the military and pro sports clubs, the senators said.

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They acknowledged that the department has, since the start of their investigation, limited what they called "paid patriotism." But McCain and Flake said the Pentagon still cannot fully account for its past spending. They hoped to ban the practice by including restrictive language in a defense appropriations bill.

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The senators also criticized the dozens of pro teams that took the Pentagon's money. In a press conference announcing their findings, McCain called on the teams to donate the funds to organizations that help troops.

Flake pointed out that, overall, pro sports teams' work on behalf of the military "dwarfs anything in these contracts.' He added, "What is upsetting is that when you see activities like this, that people assume when they go to games are paid for out of the goodness of their heart by the owners and the teams, then to find out the taxpayers paid for it, it kind of cheapens the whole lot. And that’s simply not right."

NFL Commissioner Roger Goodell wrote the senators to say the league opposed "the use of recruitment funds for anything other than their proper purpose." He also said his office was conducting an audit of all contracts between the league's 32 clubs and the military, and would refund any inappropriate payments.

The report summarizes the conclusions of an investigation McCain and Flake began last spring, when they said they discovered that weekly "hometown hero" tributes hosted by the New York Jets and New England Patriots were paid for by taxpayer money. They said they asked the Pentagon for documentation, and found $53 million in spending on marketing and advertising contracts with sports teams between 2012 and 2015, $10 million of which went to clubs in the NFL, MLB, NBA, NHL and Major League Soccer.

The senators said the Pentagon was unable to accurately account for how many contracts it has awarded or how much has been spent. The exact amount of the questionable spending isn’t clear, the lawmakers said.

Released new gov't oversight report w/ @JeffFlake on deceitful pro sports paid patriotism practices - full report: https://t.co/8hUgQotvgv — John McCain (@SenJohnMcCain) November 4, 2015

The senators said their findings offered only a glimpse of a wider problem. The Pentagon's "official response" to their request accounted for two-thirds of its contracts with major league teams, and only 70 percent of the $10 million spent.

"The Department of Defense dragged their feet every step of the way," McCain said at the press conference.

The "paid patriotism" spanned a variety of activities: on-field color guards, enlistment and re-enlistment ceremonies, performances of the national anthem, full-field flag details, ceremonial first pitches and puck drops, and hometown hero and wounded warrior tributes, the senators said.

They highlighted several events which "could be considered waste and abuse of taxpayer funds." The list included:

The unfurling of an American flag across the Georgia Dome's playing field during a 2013 Atlanta Falcons game, part of a $315,000 marketing contract.

An on-field swearing ceremony hosted by the New York Mets, at a cost of $10,000.

The honoring of five Air Force officers by the L.A. Galaxy in 2012, including sideline seats, at a cost of $1,500.

The National Guard's paying the Indianapolis Colts for use of a luxury suite, autographed items, pre- game field visits and cheerleader appearances.

National Guard's paying the Boston Bruins for a luxury box for 18 people and an executive view suite for 25 people on Military Appreciation Night.

"If the most compelling message about military service we can deliver to prospective recruits and influencers is the promise of game tickets, gifts, and player appearances, we need to rethink our approach to how we are inspiring qualified men and women to military service," the senators wrote.

Department of Defense spokesman Matthew Allen said in a statement the Pentagon's sports marketing initiatives "help to educate the public, build brand recognition, renew interest in public service and overcome negative perceptions of military that may exist among influencers and eligible youth." Much of these paid agreements are with networks, not the leagues, Allen said.

In September, the Pentagon imposed more stringent guidelines on the agreements, Allen said. Those measures included a ban on contracts that require the military to pay for honors and stricter oversight and monitoring of sports marketing agreements.