The Pentagon on Wednesday said an alleged plot by Iran to assassinate the Saudi ambassador to Washington required a diplomatic and legal response, playing down the possibility of military action.
"The US military has longstanding concerns about Iran's malign influence in the region. But with respect to this case, it is a judicial and diplomatic issue," Pentagon spokesman Captain John Kirby told reporters.
Asked if the United States had ruled out military action, Kirby said: "Only the president gets to rule in or rule out how he wants to use his military."
"This is being handled primarily through the Justice Department. That's appropriate in this case," he added.
The US Justice Department on Tuesday charged two Iranian men — including one who holds US citizenship — with conspiring to assassinate the Saudi ambassador, Adel al-Jubeir, and alleged they had backing from the Iranian Revolutionary Guard Corps.
In New York, American diplomats on Wednesday were briefing US Security Council members on the case.
"The focus right now is on continuing to apply financial and diplomatic pressure on the Iranians," Pentagon press secretary George Little said at the same briefing.
"They continue to isolate themselves, while they show no signs of stemming their own bad behavior in the region and beyond," Little said.
Iran persisted in meddling in other countries including shipping weapons to militants in Iraq who have targeted US troops there, he said.
Little said it was unclear what levels of the Iranian leadership had backed the alleged plot.
"I can't confirm at this point in terms of how high this may have been at," he said.
US Vice President Joe Biden earlier warned that Tehran would be "held accountable" and would face international condemnation for the foiled assassination alleged by US authorities.
Iran rejected the US allegations as a "mischievous scenario."
The United States in the past has refused to exclude potential military strikes against Iran over its nuclear program but top officials, including Defense Secretary Leon Panetta, have stressed that US policy is concentrated on diplomacy not military action.
