Prime Minister Manmohan Singh's wife Gursharan Kaur on Monday expressed outrage over the gang-rape of a young girl and said severe punishment should be meted out to the culprits.

She, at the same time, said any protest against the "ghastly" crime should be peaceful as it would yield more results than violent demonstrations.

The December 16 incident in a moving bus in New Delhi was a "very bad incident" and that she was at loss of words in expressing her condemnation, she said.