State and federal officials say a cyberattack was launched on election day against the Mississippi Secretary of State’s website.

Secretary of State Mike Watson reported the attack on Tuesday.

“An abnormally large increase in traffic volume due to DDoS activity caused the public-facing side of our websites to be periodically inaccessible this afternoon. We want to be extremely clear and reassure Mississippians our election system is secure and has not been compromised,” Watson reported on his website. “Our team remains committed to upholding the integrity of Mississippi’s elections process.”

Officials with the Department of Homeland Security and the Cybersecurity and Infrastructure Security Agency confirmed the attack in a media briefing Tuesday.

The cyberattack against state websites in Mississippi, including those for elections, took the pages offline by overwhelming the site with bogus traffic.

Federal officials said they have seen attacks in other states, but believe the attack on the Mississippi website was the largest sustained attack on U.S. election websites Tuesday.