US Defence Secretary Chuck Hagel has ordered a high-level review of the state of American nuclear forces, days after missile launch officers were caught in a drug investigation and dozens were accused of cheating on their certification exams. Hagel would convene a meeting in the next two weeks of officials responsible for US nuclear weapons, to examine the leadership and culture of the force, said Rear Admiral John Kirby, a Pentagon spokesman. "To the degree there are systemic problems in the training and professional standards of the nuclear career field, the secretary wants them solved," Kirby said. "And to the degree leaders have failed in their duties, he wants them held to account." The review comes as the US Air Force is investigating 10 officers for alleged illegal drug possession at six bases in the United States and Britain, some of them launch officers who are part of the intercontinental ballistic missile (ICBM) force. While acknowledging wrongdoing by some ICBM officers, Kirby said Hagel was confident US nuclear arms were secure. The probe became public on Thursday as Hagel was visiting F.E.Warren air force base in Cheyenne, Wyoming, home of about a third of the 420 US ICBMs. While there, officials revealed that two launch officers at Malmstrom Air Force Base in Montana had been implicated in the probe. It also discovered that dozens of officers had been cheating on a key proficiency exam, prompting the suspension of security clearances for 34 and the re-examination of the entire force. The drug and cheating incidents come just months after the head of US nuclear forces was fired for drunkenness and other inappropriate behaviour while on an official nuclear security visit to Moscow. There also have been concerns raised about morale problems in the force. Kirby told a Pentagon briefing that Hagel's concern about the health and morale of the workforce had been part of the reason for his visit to F.E.Warren. "He was certainly encouraged by the talent and the professionalism of those airmen with whom he interacted, but he also was reminded of the fact that not all of them live up to the same high standards required by the gravity of that work," Kirby said. The review and action plan by leaders of US nuclear forces was to be completed within 60 days, Kirby said.