NEW DELHI — Five men pleaded not guilty Saturday after being formally indicted in a special court on 13 charges, including rape and murder, in the fatal gang rape of a woman in a New Delhi bus, a lawyer said.

The men signed statements in the fast-track court saying they were innocent, said one of the men's lawyers. The lawyer cannot be identified under a gag order imposed by the court.

The court will begin hearing the evidence of witnesses on Tuesday. If convicted, the five men could face the death penalty.

A sixth suspect, who is 17, will be tried in a juvenile court and could face a maximum sentence of three years in a reform facility if convicted.

Police say the victim and a male friend were attacked after boarding a bus Dec. 16 as they tried to return home after watching a movie. The six men, the only occupants of the private bus, beat the man with a metal bar, raped the woman and used the bar to inflict massive internal injuries to her, police say. The victims were dumped naked on the roadside, and the woman died from her injuries two weeks later in a Singapore hospital.

The brutal attack set off nationwide protests, sparking a debate about the treatment of women in India and highlighting the inability of law enforcement agencies to protect them.

Also on Saturday, women's groups across the country slammed a decision by the government to bring changes in India's rape laws through an ordinance.

A government panel set up after the outcry over the gang rape and weeks of street protests by students and women examined India's criminal justice system's treatment of violence against women. After examining more than 80,000 submissions, the panel, headed by retired Chief Justice J.S. Verma, came out with a 630-page report recommending amendments to the laws governing crimes against women.

On Friday, Prime Minister Manmohan Singh's Cabinet approved an ordinance to introduce stricter penalties for crimes against women, including death in extreme cases of rape. It also approved increasing the maximum seven-year sentence for rape to 20 years and imposing stiff punishments for crimes such as stalking, cyber stalking and voyeurism.

The ordinance has to be signed by President Pranab Mukherjee to become law.

Women activists have accused the government of ignoring many key suggestions of the panel, including prosecuting army and paramilitary soldiers accused of sexual offenses and barring politicians facing rape charges from contesting elections.

"The ordinance is a complete betrayal of the faith people had reposed in the government," said Kavita Krishnan, a women's rights activist. "This is a fraud and the people are going to be out on the streets protesting this mockery of the Verma commission's recommendations."

Women's groups have appealed to Mukherjee not to sign the ordinance into law until it can be debated in Parliament.

"We are alarmed at the complete lack of transparency shown by the government. We call upon the president not to sign such an ordinance," five women's groups said in a statement.

The government said Saturday that a parliamentary committee would examine all the recommendations of the panel.

"The government is aware that we need stringent laws to protect women," said R. P. N. Singh, junior minister for home affairs. "We will discuss the recommendations and make further changes to the law that may be required."

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