California's governor has signed a law requiring presidential candidates to release their tax returns before they can be listed on the state's primary ballot.

The measure signed Tuesday by Democratic Gov. Gavin Newsom is aimed at Republican President Donald Trump, who has refused to release his tax returns. He says his returns are being audited.

The action further escalates the state's feud with the president.

The law will likely face legal action and Trump could avoid the requirement by deciding not to compete in California's primary. The major 2020 Democratic candidates have already released their tax returns.

The new law requires candidates for president and governor to submit their tax returns to California's secretary of state at least 98 days before the primary. The returns will then be posted online.