BALTIMORE—The Vatican barred Roman Catholic bishops in the U.S. from taking action to confront sex abuse, frustrating church leaders from across the country who had gathered here for their annual meeting aiming to address the crisis.

The night before the conference, the U.S. bishops’ leadership received an order from the Vatican forbidding them from taking any steps on sex abuse this year and forcing them to wait until after a global summit on the issue scheduled for February.