It's an offensive against affiliates of Andrii Derkach, a member of Ukraine's parliament and a suspected Russian agent.

Sens. Sherrod Brown and Ron Wyden want details on the reported Treasury breach and whether it will issue sanctions.

Officials are worried that sanctions could set a dangerous precedent for global behavior on the internet.

The sanctions come after the NotPetya attack and persistent attempts to break into the U.S. energy grid.