A few state and local governments appeared to be hit by a relatively rudimentary form of cyberattack that periodically made public websites unreachable. But U.S. and local officials said Wednesday that none breached vote-counting infrastructure.

“We have seen no evidence that any voting system deleted or lost votes, changed votes, or was any way compromised in any race in the country,” Jen Easterly, director of the U.S. Cybersecurity and Infrastructure Agency, said in a statement.

CISA and other federal agencies had warned that safeguarding U.S. elections has become more complex than ever, with the most serious threats from domestic sources. Foreign adversaries such as Russia, China, and Iran have tried to meddle in individual campaigns and amplify false or misleading narratives on social media.