Tehran, Aug 29 : The secretary of Iran's Supreme National Security Council Ali Shamkhani denounced US President Joe Biden's mentioning of "other options" to be used against Iran "if diplomacy fails" as "illegal threats". "The first meeting between (Israeli Prime Minister) Naftali Bennett and Biden, and the emphasis on using 'Other Options' against Iran, while being an illegal threat to another country, establishes the Islamic Republic of Iran's right to reciprocal response to 'Available Options,'" Shamkhani tweeted on Saturday. Biden said in a meeting with Bennett on August 27 that his country was committed "to ensure Iran never develops a nuclear weapon", adding that Washington would be "putting diplomacy first" and was "ready to turn to other options", reports Xinhua news agency. For his part, Bennett said he was "happy" to hear Biden's "clear words," emphasising that there are "other options" if diplomacy "doesn't work out", according to a release published on the White House's official website. Also on August 27, Zahra Ershadi, the charge d'affaires ad interim of Iran's permanent mission to the UN, delivered a letter to the Security Council, warning against Israel's "threats" against Iran's nuclear program, official news agency IRNA reported. /IANS