WASHINGTON (AP) — American officials conducted a cyber operation with Estonia this fall at that country’s invitation. That’s according to officials from both countries. The joint operation was part of an election season effort to preemptively identify cyber threats from Russia and other adversaries that could be used against U.S. networks. The U.S. Cyber Command operation occurred in Estonia from late September to early November, just as the U.S. was working to safeguard its election systems from foreign interference and to keep coronavirus research from the prying reach of hackers in countries including Russia and China. Estonian officials say they found nothing malicious during the operation.