US hid fears of radiation in Moscow embassy in 70s from staff, documents reveal

The US complained to the Soviet Union for more than a decade about microwave radiation directed at its embassy in Moscow, but kept concerns secret from embassy staff for nine years, according to newly declassified documents.

Over the years that followed, the microwave signals multiplied and intensified.

Ford was almost certainly referring to the ambassador Walter Stoessel, who became ill with leukaemia at that time, and died of the disease a decade later.

The embassy staff were finally informed in 1976. A state department telegram from February of that year said employees should be briefed in small groups but they should not pass on the details to their dependants. However, the telegram recommended that pregnant staff or family members be medically evacuated immediately for tests.

The Soviet leadership took no heed of the US complaints and it is unclear when the Moscow signal was turned off, if it ever existed. US experts were mystified over the purpose of the microwave radiation, with the two leading theories being that it was intended to neutralise electronic intelligence gathering by the embassy, or to activate listening devices built into the structure of the embassy.

When the previous embassy building was demolished in 1964, dozens of microphones had been found embedded in its walls.