Iran stands firm over reaction to murder plot

Iran's supreme leader yesterday warned that Tehran would react strongly to any "inappropriate measures" imposed by Western powers over its alleged masterminding of a plot to kill the Saudi ambassador to Washington.

The comments by Ayatollah Ali Khamenei came as Saudi Arabia formally requested United Nations Secretary-General Ban Ki-moon to notify the Security Council of Iran's actions – a move which could lead to a fresh round of sanctions against the country.

Iran's leadership has remained largely tight-lipped since the US on Tuesday accused the Quds Force, an elite unit of the Iranian Revolutionary Guard, of plotting to assassinate Adel al-Jubeir with the help of a Mexican drug cartel.

"Any inappropriate measure against Iran, whether political or security-related, will be strongly confronted by the Iranian nation," Ayatollah Khamenei said.

Iran's President, Mahmoud Ahmadinejad, also addressed the US government's allegations yesterday, saying: "Iran is a civilised nation and doesn't need to resort to assassination."

Manssor Arbabsiar, an Iranian-American used-car salesman, and his alleged co-conspirator were charged in relation to the plot last week. According to court documents, he paid a man he believed to be a cartel member – but was in fact a US government informant – $1.5m to kill the ambassador at the behest of a senior member of the Quds Force.