Iran recently held military exercises in the Persian Gulf and threatened to close key oil-shipping lanes in the Strait of Hormuz. The saber-rattling comes as Washington and its European allies tighten the economic screws on Iran as punishment for a controversial nuclear program.
The International Atomic Energy Agency last year said there may be some military aspects to Iran's nuclear program, though Tehran insists its intentions are peaceful.
Ross, a former national security adviser for President Barack Obama and Secretary of State Hillary Clinton's former point man on Iran, told Bloomberg News military tensions are high with respect to Iran.
"You have all sorts of local triggers for conflict," he said. "Having countries act on a hair trigger -- where they can't afford to be second to strike, the potential for a miscalculation or a nuclear war through inadvertence is simply too high."
Pentagon officials had said they were prepared to draft battle plans if pressed into a corner. Ross added Israel, which unilaterally struck nuclear targets in Iraq and Syria, could easily target Iran.
"They certainly have the capability by themselves to set back the Iranian nuclear program," he said, adding there is still time for a more amicable settlement.
"Force is not inevitable," he said. "Diplomacy is still the desired means."