Bollywood celebrities have expressed grief and anger over the brutal gang rape of a student in the national capital that has shocked the nation.

Actress and activist Shabana Azmi termed the incident "horrific" and said it points to "a shocking state of affairs".

"What we really need to do is to use this shocking incident as a wake-up call to demand fast-track courts, speedy justice, and a process of investigation that is firm; there has to be the certainty of punishment for the accused," said Shabana.

The savage rape and torture of the 23-year-old by at least six men occurred Sunday night when the woman and her male friend boarded a private bus, used for ferrying school children, in south Delhi after watching a movie.

The victim, battling for life at the Safdarjung Hospital in Delhi, was brutally assaulted in the moving bus. Her male friend, who tried to save her, was beaten up by the rapists. Both were dumped by the roadside after some 40 minutes.

The shocking incident, which has resulted in widespread street protests across the country, has had its impact in Mumbai as well.

"I can't imagine that kind of brutality," said actress Soha Ali Khan, "it makes one incredibly enraged when you think about it."

"I can't imagine what the victim and her family are going through my heart bleeds for her and I hope that she survives and that she fights and goes on to live a wonderful life. I am just praying for her well being at the moment."

Music Composer A.R. Rahman felt doomsday had arrived. "It is doomsday because somebody has done such a big harm to humanity. It is disrespect to humanity. If you don't fix it now, it is shame for the nation," said the Oscar winner.

Former member of Parliament and actress Hema Malini, herself a mother of two, has advised girls to stop taking their security lightly.

"When my daughters go out of home and when they come late at night, I get very worried. I keep calling them all the time. I tell them to take our driver and don't go with any stranger. So my advice to all the children of this country, especially girls, don't take it so lightly and just walk out. Anything can happen with anybody."

The rape victim continues to battle for her life after an operation to remove her entire intestine, and doctors said Friday that she remains critical.