When Joe Biden’s presidential campaign released his ambitious climate change plan Tuesday, it landed almost immediately with accusations of plagiarism.

Josh Nelson, vice president of CREDO mobile, a phone company based in San Francisco that raises money for progressive organizations, first highlighted instances of plagiarism Tuesday morning on Twitter.

Reports by Business Insider and conservative news site The Daily Caller found other instances of plagiarism, in which Biden’s 2020 Democratic presidential campaign uses phrasing that is identical or nearly identical to literature by other organizations.

In response to the allegations, the Biden campaign told HuffPost it had “inadvertently left out” “several citations” in the final version of the climate plan and have since updated the campaign website to include those sources.

Nelson revealed two instances where the former vice president’s plan, which was published to his campaign site early Tuesday, included sentences identical to material from two environmental organizations: Blue Green Alliance and the Carbon Capture Coalition’s Center for Climate and Energy Solutions (C2ES).

Biden’s plan appeared to have lifted a sentence from the Blue Green Alliance’s 2017 letter to the Senate Environment and Public Works Committee and the C2ES website.