Obama: Iranian government knew of assassination plot, no options off table

President Obama said Thursday that Iranian government officials had knowledge of a plot to kill the Saudi ambassador to the U.S., but the president stopped short of calling the planned assassination an act of war.

Obama did try to up the ante after Secretary of State Hillary ClintonHillary Diane Rodham ClintonChris Murphy’s profile rises with gun tragedies DNC, RNC step up cyber protections Gun proposal picks up GOP support MORE said the plot, disrupted by the Justice Department, represented a "dangerous escalation" by Iran.

"This is not just a dangerous escalation," Obama said at a joint press conference with the president of South Korea. "This is a pattern of reckless and dangerous behavior by the Iranian government."

But Obama did not describe the plot as an act of aggression by the Iranians, and he largely deferred questions about the plot and the arrest of one of the suspects to Attorney General Eric HolderEric H. HolderEric Holder group to sue Georgia over redistricting Eric Holder to Trump: 'Taking a knee is not without precedent' Juan Williams: Momentum builds against gerrymandering MORE.

The president did say repeatedly that Iran will have to "pay a price" for its involvement in such a plot, but he said that sanctions and isolation from an increasingly unified international community are the steps he is considering.

Still, he said, "we don't take any options off the table" when it comes to Iran.

Obama did seem to respond to claims by the Iranian government that the plot was fabricated by the U.S., saying that there is proof the would-be assassin "was paid by and directed by individuals in the Iranian government."

"Those facts are there for all to see," Obama said.