[Heatseeker]

It's an interesting topic. As I recall, the nuke story was generally attributed to fears seeded into New China News Agency (now known as Xinhua News Agency) articles that the USSR might use nuclear weapons.

A declassified "Intelligence Note" from the State Department's Bureau of Intelligence and Research, of June 3rd 1969, briefly touches on this.

However I've never seen any evidence such weapons were actually used.

[MadJack]

I remember hearing something about the Sovs using Fuel-Air Explosives during the border fighting. A possible explanation for the nuke stories?