Here is a TLDR from the article:

The U.S. Treasury Department said in a statement the entities - a subsidiary of Iran's Revolutionary Guard Corps (IRGC) and an organization affiliated with Russia's military intelligence agency (GRU) - aimed to "stoke socio-political tensions and influence the U.S. electorate during the 2024 U.S. election".

Here is a direct link to the US Treasury Department's press release discussed in the Reuters article:

https://home.treasury.gov/news/press-releases/jy2766