The Stimson Center, a nonpartisan think tank based in Washington, D.C., has published a report warning that American nuclear weapons stored at Turkey’s Incirlik Air Base could be captured by “terrorists or other hostile forces.”

“Whether the US could have maintained control of the weapons in the event of a protracted civil conflict in Turkey is an unanswerable question,” said the report, alluding to the recent coup attempt in Turkey.

“From a security point of view, it’s a roll of the dice to continue to have approximately 50 of America’s nuclear weapons stationed at Incirlik Air Base in Turkey,” co-author Laicie Heeley told AFP.

“There are significant safeguards in place… But safeguards are just that, they don’t eliminate risk. In the event of a coup, we can’t say for certain that we would have been able to maintain control,” she added.

AFP points to a few others who have expressed concerns about the Incirlik nukes after the coup attempt, including White House National Security Council veteran Steve Andreasen, who said, “we have ample evidence that the security of U.S. nuclear weapons stored in Turkey can change literally overnight.”

Others have argued the weapons cannot be armed without authorization from the United States, reducing the risk that hostile forces could make use of them. Another part of the Stimson report argues that U.S. nuclear weapons are in serious need of modernization, which could reduce confidence that the weapons are impervious to hacking. The propaganda value of stealing even useless nuclear warheads from a U.S. facility would also be considerable.

According to Business Insider, Congress received a briefing on the Incirlik Air Base and its nuclear arsenal last week — which may constitute the “most official confirmation of the location of the bombs on record.”

“The weapons at Incirlik are the shorter-range variety, and they are mainly valuable to deter potential aggression and demonstrate the US’s commitment to NATO,” Business Insider explains:

However, Incirlik is unusual in that Turkey does not own or maintain nuclear-capable aircraft, and Ankara does not allow the US to fly nuclear-capable bombers to that airbase. So the bombs that sit in Incirlik can’t actually be used, or they would have to be hauled to another base first.

The congressional briefing judged the security situation of the bombs “adequate,” noting the underground storage facility was updated in 2015, and aspiring thieves would need to “overwhelm U.S. and NATO forces on one of their own bases, and then come up with some way to haul a 12-foot long, very heavy warhead.”

Those both sound like surmountable obstacles for a coup or terrorist insurgency that could overthrow the government in Ankara, posing a far greater threat to Incirlik than merely turning off the power for a while, as last month’s unrest did.

In the L.A. Times op-ed referenced by AFP, Steve Andreasen noted that the Turkish base commander at Incirlik was arrested for allegedly playing a role in the coup, which brought the unrest awfully close to American forces and the nuclear weapons they are guarding. He also worried that anti-American sentiment in Turkey, due to America’s reluctance to hand over accused coup mastermind Fethullah Gulen, is growing uncomfortably reminiscent of Iran circa 1979.

Arguments have been made for relocating the nuclear warheads from Incirlik, but as Business Insider notes, such a move would also be taken as a loss of faith in Turkey and/or NATO. Also, NATO concern over Russian aggression doesn’t look like a relic of Cold War paranoia these days.

Andreasen, who thinks American nukes should be recalled from Europe as well as Turkey, rejected those arguments: “In the wake of an incident at a nuclear storage site – for which the U.S. would be held accountable and suffer long-term consequences with allies – it would be difficult to explain that vulnerable targets were left in place due to a perceived need to reassure our allies.”