(Reuters) - Republican attorneys general from 20 U.S. states sued the Biden administration on Tuesday, seeking to block new reforms to the U.S. environmental review process for major projects such as transmission lines and wind and solar farms.

States including Iowa, North Dakota, Texas and Florida challenged reforms included in a rule finalized in April by the White House Council on Environmental Quality in North Dakota federal court, arguing they go beyond the agency's authority, would increase project costs and unfairly favor clean energy projects.

The reforms aim to streamline analysis under the National Environmental Policy Act, or NEPA, a bedrock environmental law that requires environmental reviews for major projects that receive federal permits or funding. NEPA reviews are the frequent focus of litigation, which can delay construction on projects for years.

The states said the regulations also require agencies to consider a wider range of a project's impacts during environmental reviews including climate change and environmental justice considerations, which will cause project delays even though those factors are not explicitly detailed in NEPA's text.

They said the rule changes will make it more difficult for some projects to receive approvals if they might impact disadvantaged or minority communities.

The rule will impose improper bureaucratic roadblocks for projects including highways or fossil fuel power plants "by forcing social, environmental and race-based regulations on developers," the states said in a statement.

A White House spokesperson said the rule will speed up project reviews and make sure industry can move forward with key investments and projects, but declined to comment on the lawsuit directly.

The reforms build on and expand initial work to reform the NEPA process finalized in 2022, when the Biden administration began rolling back Trump administration changes that made the process less stringent.

The earlier Biden administration changes required federal agencies to consider the direct, indirect and cumulative impacts of proposed projects or actions.

The White House's Council on Environmental Quality has called the newest reforms a "core element" of Biden's efforts to build out clean energy systems and to rebuild American infrastructure.

It said in April that the new reforms are consistent with the agency's legal authority.

(Reporting by Clark Mindock, Editing by Alexia Garamfalvi and Lincoln Feast.)

By Clark Mindock