US military chief General Martin Dempsey denounced ex-officers Tuesday for waging a campaign against President Barack Obama, arguing that soldiers had a duty to stay above the political fray.

Wading into a potential minefield during a hotly contested White House race, Dempsey voiced his disapproval of a group of retired military members and CIA officers who have accused Obama of spilling sensitive national security details to help secure his re-election.

Asked if the group’s criticism was valid or useful, Dempsey, chairman of the US Joint Chiefs of Staff, said he would not comment on the substance of their allegations.

But he added: “As to the latter, is it useful? No, it’s not useful. It’s not useful to me.”