While researching the Siberian Seven for Has anyone else been holed up in a foreign embassy like Julian Assange?, I read this article from 1981 that said there may be another problem with them staying at the embassy:
…in a few years, even that could conceivably present problems: The embassy is scheduled to move to new quarters.
Out of sheer, unadulterated curiosity, I figured, why not find out where they moved to? The story behind this is much better than I thought though. Construction for the new building began two years before that article was written in 1979. In 1985, during construction, Americans discovered that the support beams constructed by the Russians for the embassy had been wired for sound. The entire American embassy was just one big wire leading directly to the KGB. This was obviously a problem.
Americans abandoned that site and refused to allow Russians to occupy their site in Washington DC until 1994. (Coincidentally, Americans built a spy tunnel under this Russian Embassy. Though, apparently, they were able to find out about it by one of their spies.) It wasn’t until the year 2000 (19 years after the original article was written) that Americans began occupying the new embassy. (An American crew secured the upper floors of the embassy. The lower floors are still potentially bugged though.)