The US bugged the “toilet partitions” of the Russian embassy in D.C. during its construction[0] and the FBI built a tunnel under it for espionage purposes in the 80s[1].
[0] https://www.cia.gov/readingroom/document/CIA-RDP90-00965R000...
[1] https://web.archive.org/web/20100514112651/http://articles.o...