The activation of Tehran’s emergency air raid siren system had nothing to do with any alleged aerial threat emanating from Israel or its F-35 fighter jets, Tasnim has reported, citing an official said to be informed with the situation.
“Last night’s incident had nothing to do with any aerial threats which would activate the country’s air defence system,” the official told the news agency.
According to Tasnim, speculation is “rampant” on social media in Iran after sirens were heard wailing in western Tehran, with some people speculating that the sirens may have been activated by Israeli F-35s operating over Iranian airspace. The rumours were amplified by Radio Farda, the Iranian branch of the US government-funded Radio Free Europe/Radio Liberty broadcast service.
Tehran Deputy Governor Hamid Goodarzi, who is responsible for security affairs, told local media that the sirens went off due to a technical glitch, dismissing any threats to public safety.
Social media users posted footage of the air raid sirens as they blared on Friday night.
#BREAKING: The Air raid sirens across #Tehran/#Iran are active now.Unclear if anything is happening or those are just training drills.#BreakingNews #alert #إيران pic.twitter.com/LXYT45pKKN
— The Only Truth (@TheOnlyTruthInc) January 29, 2021
Sirens in Shahr Ara and Marzdaran areas, western #Tehran#Iran
— Aleph א ☕ (@no_itsmyturn) January 29, 2021
Lady says:
"What's this sound? it's wailing for 5-10 minutes" pic.twitter.com/yS8ZoYzx5N
Friday’s incident wasn’t the first time that rumours have spread online about the Israels "testing" their F-35s against Iran’s air defences, with a Kuwaiti newspaper claiming two years ago that the fifth-gen stealth fighters had crossed through Syria into Iraq and into Iran, where they supposedly carried out reconnaissance in Bandar Abbas, Isfahan, and Shiraz.
Tehran also says that it has the advanced strategic and mobile radar capabilities necessary to detect enemy aircraft, including those with stealth capabilities. In June 2019, the Khordad-3, an Iranian-made medium-range missile system, shot a stealthy $220 million US Global Hawk surveillance drone out of the sky over the Strait of Hormuz.

The wailing of the sirens Friday night comes amid heightened tensions in the region, with the administration of President Biden flying B-52 strategic bombers over the Middle East just days into his presidency, despite reports of negotiations between Tehran and Washington on US reentry into the Iran nuclear deal.