TEHRAN — Perplexed residents here focused their eyes — and smartphones — upward on Monday afternoon as antiaircraft weapons hidden on rooftops suddenly began blasting away at “an unidentified flying object” in the clear sky.
The thunderous clack-clack of gunfire and small dots of white smoke overhead provided a loud and unexpected accompaniment to the start of city’s evening rush, as videos show.
Traffic slowed to a near standstill.
It was the second time in a month that antiaircraft guns had opened fire in Tehran, Iran’s capital. And both times the target turned out to be, according to the authorities, a camera drone.
“It was like a series of explosions, our windows shook. My husband was in a panic, but I was not. I didn’t see anything,” Mojgan Faraji, a journalist, said on Monday. Videos quickly spread across social media.
But as is often the case in Iran, exactly what happened was open to interpretation.
“The drone was flying close to a forbidden zone,” Ali Asgar Naserbakht, a city official, told the state news agency, IRNA. He was probably referring to a government compound in the center of Tehran where President Hassan Rouhani and Iran’s supreme leader, Ayatollah Ali Khamenei, have their offices.
“An investigation will be started into what institute or organization controlled it,” Mr. Naserbakht added.
Iran’s antiaircraft forces, who protect strategic places like the nuclear test reactor in the western part of the city and the airports in the south, are the last line of defense in case of an aerial attack. Placed in strategic rings around the city, sometimes covered under camouflage nets, they are rarely seen — or heard.
On Monday though, it seemed as though the entire city had not only heard them but also managed to film some as they were firing toward the sky from rooftops.
In December, a camera drone was shot down in the same area. At the time, officials said there had been a mix-up and that the device belonged to state television, which had been filming the weekly Friday prayer session. That day, however, the event was organized somewhere else, inside a mosque. Representatives of state television denied that they had a drone in the area, and no images of the debris were made public.
It was unclear when or how the second drone was spotted on Monday, but after one of the antiaircraft positions, on a rooftop near Tehran University, opened fire, several fighter jets were also deployed, the semiofficial Tasnim news agency reported. Although military sources denied this later, witnesses said there were shots being fired for about 10 minutes.
Officials emphasized that there was no need for concern about antiaircraft fire in the center of the city. “There is nothing to worry about,” Alireza Elhami, the deputy commander of Iran’s air defense organization, told the semiofficial Fars news agency. “A very light camera drone entered the no-fly zone. It left after the first shot.”
Other officials gave contradictory accounts, saying either the drone had been “shot down” or that “the drone escaped.” All praised the high level of security in Tehran, one of the few capitals in the Middle East not rattled by bombings, Mr. Elhami pointed out.