The only thing about this post title that should surprise you is that they were spotted (of course they went away ASAP). Whether you call them spies, spotters, or advisers, “Western men” have always interfered in the events of countries whose policies do not please the politicians or corporate powers. Usually such interference is justified as necessary to protect our “way of life,” even though it is not always necessary to explain their role to their own citizens. But you can find them if you read Western history
Salvador Allende, the first democratically-elected Socialist, was opposed by Richard Nixon who feared the spread of Communism and ordered the CIA to do anything they could to stop Allende. HERE foreign involvement section. Advisors (and yes they had weapons) were in Viet Nam as early as 1962. The CIA set up the rebels in Afghanistan in an effort to destroy the USSR, my previous post HERE
Find your own example of any western insertion of troops despite government or international regulations against them and post it in the comment section here for others to read.