The Iranian Foreign Ministry has issued a statement dismissing U.S. accusations that Iran was involved in a plot to assassinate a Saudi ambassador as “irrational” and possibly a “political and media show.”

ISNA reports that in a statement issued on Saturday, the ministry says: “The basis of U.S. officials’ contentions is merely the report of an unknown undercover agent, which is in turn based on the claims and guesswork of individuals involved in drug smuggling.” It adds: “They have presented no legally acceptable evidence to back their allegations.”

Last Tuesday, U.S. officials announced that the Islamic Republic, through the international branch of the IRGC, the Quds Force, planned to assassinate the Saudi ambassador to the U.S.

They added that they had already arrested an Iranian, Mansour Arbabsiar, in connection with the plot.

The announcement says the “illogical behaviour of the U.S. government in fabricating this scenario” can only be explained in light of “the failure of U.S. foreign policy” against Iran as well as America’s “growing internal problems.”

It goes on to accuse the U.S. of creating “tensions and disrupting international security.”

The U.S. allegations have already moved a number of Western countries to discuss tougher sanctions against Iran. British Prime Minister David Cameron has announced that sanctions are being considered, but his government will not back any military attacks against Iran.

Meanwhile, Saudi Arabia is examining the case to decide on an “appropriate response.”