TRAVERSE CITY, Mich. (AP) — A federal appeals court has blocked an Obama administration rule that attempts to clarify which small streams, wetlands and other waterways the government can shield from pollution and development.

In a 2-1 ruling Friday, a panel of the Sixth U.S. Circuit Court of Appeals in Cincinnati put the regulations on hold until the court decides whether it has jurisdiction to hear challenges to the rules by 18 states.

The Environmental Protection Agency and the U.S. Army Corps of Engineers issued the regulations in May after two Supreme Court rulings left uncertain which waterways can be protected under the Clean Water Act.

States challenging the rules say they go too far and could be costly to landowners, while the government says they would safeguard drinking water for 117 million Americans.