Elon Musk's X has challenged a New York state law that requires social media companies to disclose how they monitor hate speech, extremism, and other contentious content.

In a lawsuit filed on Tuesday, the social media platform, formerly known as Twitter, argues that the law forces companies to disclose "highly sensitive and controversial speech" that is protected under the Constitution's First Amendment.

New York Attorney General Letitia James, who is in charge of enforcing this law, is the named defendant in X's lawsuit.

Social media sites have become the main source of news for Americans, with the majority consuming it on networks like X, according to new research from the Reuters Institute.

Deciding what content is acceptable on social media platforms "engenders considerable debate among reasonable people about where to draw the correct proverbial line," X said. "This is not a role that the government may play."

The Stop Hiding Hate Act, passed in December, requires social media companies to disclose steps they take to eliminate hate on their platforms, and to report their progress.

In a statement on Tuesday, the two New York state lawmakers who sponsored the Stop Hiding Hate Act called social media companies like X "cesspools of hate speech" and said the law did not violate the First Amendment.

Social media platforms, including X, "have consistently failed to inform the public about their policies regarding hatred and misinformation", Senator Brad Hoylman-Sigal and Assemblymember Grace Lee said.

Neither New York Attorney General Letitia James nor X replied to the BBC's request for comment on Tuesday.

X's lawsuit against New York state comes nine months after the company successfully blocked a California law that required large social media companies to submit reports about their content-moderation policies.

The company extensively cited its earlier victory in its Tuesday's lawsuit and criticised New York lawmakers for failing to revisit the legislation's language even after the California law was largely struck down.

Musk, who acquired X in 2022, has dramatically scaled back the rules that govern what content and behaviours are acceptable on the platform, according to Professor Laura Edelson, who teaches computer science at Northeastern University.

He has "also significantly reduced the resources the platform puts into enforcing even the rules it does still have," she said. "This is why, even though rules around spam haven't changed on X, there is so much more floating around than there used to be."

Last year, a federal judge dismissed a lawsuit brought by Musk against a research group that documented an uptick in hate speech on the site.