A new report released Wednesday found that K-12 schools in the United States experienced a “record-breaking” number of cyber incidents during 2020 as classes moved online and hackers moved in on vulnerable targets in the midst of the COVID-19 pandemic.

The report, put together by the K-12 Cybersecurity Resource Center, tracked 408 cybersecurity incidents that hit K-12 institutions over the past year, an 18 percent increase from 2019 and an average of two cyberattacks per school day aimed at the nation’s education system.

These attacks included ransomware attacks, in which a hacker holds a network for ransom, data breaches of student and teacher private data, and class intrusions such as “Zoombombing,” which plagued online classes during the pandemic.

The report was rolled out as part of a virtual conference on Wednesday, at which Rep. Jim Langevin (D-R.I.) announced he would reintroduce legislation previously rolled out last year with Rep. Doris Matsui (D-Calif.) that would provide resources to help protect K-12 institutions from cyberattacks.