The lawsuit alleges that Maine is violating Title IX, which affords legal protection against sex discrimination, by allowing transgender female athletes to participate in girls' and women's sports.

The lawsuit cites two instances in which transgender athletes won girls' competitions, including a pole vaulter who won the state indoor track and field state championships in February.

When asked on Wednesday whether it's worth the department's resources to sue Maine over two athletes, US Attorney General Pam Bondi replied, "I don't care if it's one. I don't care if it's two. I don't care if it's 100."

Bondi said the department is also probing transgender issues in other states including Minnesota and California.

Maine Governor Janet Mills said in a statement on Wednesday that the suit was an example of Trump trying to impose his will on state governments.

"This matter has never been about school sports or the protection of women and girls, as has been claimed, it is about states rights and defending the rule of law against a federal government bent on imposing its will, instead of upholding the law," Mills said. "Let today serve as warning to all states: Maine might be among the first to draw the ire of the Federal government in this way, but we will not be the last."

Trump frequently railed against transgender athletes while on the campaign trail and signed an executive order banning transgender athletes from competing in women's sports. He prominently clashed with Mills, a Democrat, over the issue at a February White House meeting.

Proponents of Trump's action say it protects the fairness of competition, while opponents say it excludes young transgender people from important physical and social activity.

The majority of Americans do not support transgender athletes competing in girls' and women's sports, polling shows. Just 26% of respondents to a February Reuters/Ipsos poll agreed that they should at the elementary and high school level, with 55% opposed and the rest unsure. Just 19% supported the idea of transgender women competing in elite-level women's sports, like college, the Olympics and professional leagues, with 65% opposed.

Maine is expected to see competitive House and Senate races in next year's midterm elections that will help determine control of Congress.

--Reuters--