They're in the American embassy and consulates.

From the article:

“These skilled and highly trained special agents focus on a wide variety of serious crimes, like drug trafficking, child exploitation, weapons smuggling, human smuggling, financial fraud, and more.”

TLDR: They're not armed and can't arrest people.

In my opinion, it was all entirely reasonable when the US administration was an ally and a civilised democracy. It might be something we should re-evaluate for current circumstances.