While many NATO members house US nuclear weapons, according to Pentagon spokesman Air Force Lt. Col. Uriah Orland “it is U.S. policy to neither confirm nor deny the presence or absence of nuclear weapons at any general or specific location.” During a meeting with the Italian President, Trump confirmed the presence of US nuclear weapons at a specific Turkish air force base.

The Washington Post – Trump appears to confirm U.S. nukes are in Turkey, an admission that would break with longstanding protocol
Associated Press – Some worries about nuclear weapons at Turkey base
CNN – Trump appears to confirm open secret about US nuclear weapons in Turkey