A vice admiral who is second in command at the United States Strategic Command, which oversees nuclear war-fighting forces for the military, has been suspended amid an investigation into his possible involvement in illegal gambling, officials said on Saturday.

The officer, Vice Adm. Timothy M. Giardina, is a highly decorated sailor with more than three decades in the Navy. The suspension occurred on Sept. 3, but was not announced publicly, said Capt. Pamela Kunze, the command’s spokeswoman.

Captain Kunze would not comment further on the circumstances surrounding the suspension, citing a continuing investigation by the Naval Criminal Investigative Service.