An army of Chinese-controlled social media bots is attempting to influence voters in Alabama, Texas and Tennessee, while denigrating U.S. Sen. Marco Rubio of Florida, according to new research published on Wednesday by Microsoft.

The operation represents a coordinated interference effort against down-ballot races, experts say, in which the fake accounts are belittling U.S. Rep. Barry Moore of Alabama, U.S. Rep. Michael McCaul of Texas, Tennessee U.S. Sen. Marsha Blackburn and Rubio, all Republicans.

The troll network has "parroted antisemitic messages, amplified accusations of corruption and promoted opposition candidates,” according to Microsoft.