(Credit: U.S. Navy/AP Photo)

WASHINGTON - The No. 2 officer at U.S. Strategic Command has been suspended and is under investigation by the Naval Criminal Investigation Service for what U.S. officials say involves issues related to gambling, Stratcom announced today.

U.S. Strategic Command, based in Bellevue, Neb., oversees the military's nuclear units and weapons.

Stratcom commander Gen. Robert Kehler suspended Vice Adm. Tim Giardina from his duties as deputy commander on Sept. 3 according to a Stratcom spokesperson.

Capt. Pamela Kunze said Kehler has also sent a recommendation to Defense Secretary Chuck Hagel that Giardina be reassigned from his post. However, she said, "It is undetermined what if any additional actions will occur because the matter is under investigation" by NCIS.

Kunze would not elaborate on what had prompted the investigation.

"The circumstances surrounding the investigation remain under investigation so it would be inappropriate to comment further," Kunze said.

Two U.S. officials familiar with the investigation told ABC News that it involved issues related to gambling, and one added that misleading statements were also involved. A defense official said there is nothing to indicate there's been any compromise of Stratcom's mission or classified material.

Giardina remains Stratcom's deputy commander, though he is not carrying out the duties associated with the job that he has held since December 2011. His suspension was first reported by the Omaha World-Herald.

Kunze said that in June a non-Defense Department law enforcement agency began investigating Giardina and contacted Stratcom on July 16. The next day, Kehler asked that NCIS begin an investigation. Based on information gathered from that investigation, Kehler decided on Sept. 3 that Giardina should be suspended.

Giardina was scheduled to leave Stratcom later this year and his successor, Lt. Gen. James Kowalski, had already been nominated by the White House.