(Reuters) - Seven states, Catholic groups and individuals Thursday filed the first major lawsuit challenging the Obama administration's new contraceptive regulations, arguing that the policy violated the constitutional rights to religious freedom.

Florida, Michigan, Nebraska, Ohio, Oklahoma, South Carolina and Texas joined with Catholic organizations and two Catholic plaintiffs to fight the new rules issued earlier this month requiring healthcare coverage for free birth control.

The Obama administration initially proposed that religious-affiliated groups such as charities, hospitals and universities - but not churches - provide free contraceptive coverage to female employees as other healthcare providers must do.

But after a firestorm of criticism from religious leaders and with November election looming, President Barack Obama had to pull back and the regulations were rewritten to provide an exemption to religious organizations.

The compromise shifts the burden to insurance companies, ordering them to provide workers at religious-affiliated institutions with free family planning if they request it, without involving their employer.

That did little to satisfy many religious groups and conservatives in key states that will be the battleground in the 2012 presidential election, like Ohio and Michigan, where Republican attorneys general joined other states to sue.

Any rule, regulation or law that forces faith-based institutions to provide for services that violate their free exercise of religion, or that penalizes them for failing to kneel at the altar of government, is a flat-out violation of the First Amendment, Michigan Attorney General Bill Schuette said in a statement.

A Justice Department spokeswoman was not immediately available for comment.

The 25-page lawsuit, filed in federal court in Nebraska, argued that the regulations represent an unprecedented encroachment on the liberty of religious organization employers and that the religious exemption offered is insufficiently narrow.

The states, religious groups and individuals also argued that they could be at immediate injury from the new regulations despite the one-year delay in enforcement, saying that it could be withdrawn at anytime.

The case is State of Nebraska et al v. U.S. Department of Health and Human Services et al; No. 12-cv-3035, in U.S. District Court for the District of Nebraska

(Additional reporting by Karen Pierog in Chicago; Editing by Eric Beech)