Microsoft announced late Monday that it thwarted a spearphishing attack against the U.S. Senate by a group affiliated with Russian intelligence.

In a statement, the tech giant said its digital crimes unit “executed a court order to disrupt and transfer control of six internet domains created by a group widely associated with the Russian government.”

The group is known as Strontium, Fancy Bear and APT28 and was also recently named in an indictment from special counsel Robert S. Mueller III’s investigation into Russian interference in elections, NBC News reported.

Microsoft said the transfer control showed Strontium targeted the U.S. Senate but wasn’t specific about which offices were targeted.

Strontium also appeared to target conservative think tanks the Hudson Institute and the International Republican Institute.