Federal regulators say recent surprise inspections show that despite increased enforcement, underground coal mines continue to violate safety laws.

Mine Safety and Health Administration director Joe Main says it's appalling to keep finding the egregious violations revealed by the agency Tuesday.

MSHA says it found miners working under an unsupported roof at a Tennessee mine, and sections of a West Virginia mine were closed after inspectors found numerous serious violations.

Other problems turned up at two Kentucky mines, including an International Coal Group operation that was issued 43 citations last week.

An ICG spokesman had no immediate comment.

MSHA stepped up enforcement following an April explosion that killed 29 in West Virginia.