US nuclear weapons 'at risk of seizure' from Turkish base
Dozens of US nuclear weapons stored at a Turkish air base near Syria are at risk of being captured by "terrorists or other hostile forces", a Washington think tank said on Monday.
The US has an estimated 50 nuclear bombs at Incirlik in southern Turkey, 110km from the border with Syria.
The base's Turkish commander was arrested on suspicion of complicity in last month's coup plot.
"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 Monday's report from the Stimson Center, a nonpartisan think tank working to promote peace.
Incirlik is a vital base for the US-led coalition fighting the Islamic State (IS) group in Iraq and Syria, giving drones and warplanes fast access to IS targets.
But the US defence department in March ordered families of US troops and civilian personnel stationed in southern Turkey to leave due to security fears.
"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," report co-author Laicie Heeley said.
"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 told AFP.
'Avoided disaster so far'
The bombs are believed to be kept at Incirlik as a deterrent to Russia and to demonstrate America's commitment to NATO, the 28-member military alliance that includes Turkey.
The issue has been the subject of renewed debate in the United States since the coup attempt.
"While we've avoided disaster so far, we have ample evidence that the security of US nuclear weapons stored in Turkey can change literally overnight," Steve Andreasen, director for defence policy and arms control on the White House National Security Council staff from 1993 to 2001, wrote in the Los Angeles Times last week.
Kori Schake, a fellow at the California-based Hoover Institution, noted in a written debate in the New York Times that "American nuclear forces cannot be used without codes, making the weapons impossible to set off without authorisation".
"The fact that nuclear weapons are stationed in Turkey does not make them vulnerable to capture and use, even if the country were to turn hostile to the United States," she argued.
The defence department declined to comment on questions arising from the Stimson study.
"We do not discuss the location of strategic assets. The [department] has taken appropriate steps to maintain the safety and security of our personnel, their families, and our facilities, and we will continue to do so," it said in a statement.
The Incirlik concerns were highlighted as part of a broader paper into the Pentagon's nuclear modernisation programme, through which the US would spend hundreds of billions of dollars to update its arsenal.
The authors say the B61 gravity bomb, 180 of which are kept in Belgium, Italy, Germany, the Netherlands and Turkey, should be immediately removed from Europe.