The Weather Channel was hit by a ransomware attack on Thursday, briefly taking a live TV program off the air, according to a Wall Street Journal report.

The attack came amid severe weather in the southeastern United States and knocked out the cable channel for more than an hour. The FBI told the Journal a ransomware attack was the source of the problem and that the agency is investigating.

“We experienced issues with this morning’s live broadcast following a malicious software attack on the network,” the channel confirmed in a tweet about the incident, adding that “backup mechanisms” had allowed the channel to restore service. “We apologize for any inconvenience to viewers as we work to resolve the matter,” the tweet said.

Earlier in the day, the channel said it was “experiencing technical difficulties” with its live broadcast. In another tweet posted soon after, the channel said it was “back live on the air to bring you the latest on today’s severe weather threats.”

What the hackers were demanding in the attack isn’t clear, but ransomware, a type of malware used to extort money from targets, has become a major headache for businesses and governments. In one of the most devastating examples, a strain of ransomware called WannaCry, believed to have been developed by North Korea, spread throughout the world in 2017. The attack eventually affected computers in more than 150 countries.