Swiss diplomatic mission had represented US in Iran since 1979 Islamic Revolution
Iran's police opened on Tuesday an investigation into the death of a senior employee of Switzerland's embassy in the country.
The woman, who is said to be a Swiss national in her 50s, died after falling from a 20-story building in the capital of Tehran, where she resided, state media report.
A report in Iran's Mehr agency identified the deceased as a 51-year-old first secretary with the diplomatic mission.
The police were alerted of her disappearance on Tuesday and found the body; as per the Mehr report, the woman had been dead "for a while."
Switzerland confirmed the fatal incident but did not shed any further light on the diplomat's identity for privacy concerns.
The diplomats are keeping contact with the local investigators, the country's Foreign Ministry added, refusing to share more on the circumstances of the death.
After ties between the US and Iran were severed on the back of the 1979 Islamic Revolution, the Swiss diplomatic mission came to become a de-facto liaison between Washington and Tehran.
The development comes as the US and Iran are engaged in intense talks on Washington rejoining the 2015 Iran nuclear deal; earlier this week, the US also rejected Iran's reports of a prisoner swap deal between the two nations.