* Armed forces ordered to cancel parties
* Clubs call off celebrations, vigils planned
* Government promises tough new laws
NEW DELHI, Dec 31 (Reuters) - India's armed forces cancelled New Year's Eve parties on Monday, reflecting the sombre mood across the country after the gang rape and murder of a student that triggered an international outcry.
High-end clubs, politicians and ordinary Indians also called off celebrations as a mark of respect for the 23-year-old woman who died on Saturday two weeks after her brutal assault.
The attack prompted protests and a national debate that revealed deep fissures in Indian society, where staunchly patriarchal views about women clash with a fast-modernising urban culture.
Authorities clamped down on demonstrations in the heart of the city before Christmas, but hundreds of people gathered for vigils on Monday night and more events were planned across the city.
The army, navy and air force were ordered to cancel any parties, said a defence ministry spokesman.
"There is no New Year celebration ... There will be a candlelight tribute at 6 pm. After that the club will be closed," said Rajiv Hora, secretary of the Delhi Golf Club in the centre of the capital.
The Press Club of India and the ruling Congress Party also cancelled parties as did the Gymkhana Club, a private members' organisation known for its lavish end-of-year celebrations.
The Dec. 16 attack highlighted an epidemic of violence against women in India, where one rape is reported on average every 20 minutes.
"We are extremely concerned about the number of rape cases throughout India and the widespread pattern of violence against women," said Lise Grande, U.N. Resident Coordinator in India.
"It is alarming that too many of these cases are children. One in three of the rape victims is a child," she added.
The protests over the attack caught authorities by surprise and forced them to promise tough new laws and swift action to punish attackers and protect women.
The government has set up two panels headed by retired judges to recommend measures to ensure women's safety.
"In the New Year, there should be a revision of all laws related to crimes against women," Sushma Swaraj, a senior leader from the main Bharatiya Janata Party (BJP), told a gathering of supporters in the capital who met to express solidarity with the victim.
"We have asked the government to convene a special session of parliament where we can discuss the issue," Swaraj added.
A senior Congress party official told Reuters the government and main opposition parties had agreed there was a need for more severe punishments for sex offenders.
The Congress party was also discussing the option of including chemical castration as a penalty in future legislation, added the official, who asked not to be named.
Police detained five men and one teenager in connection with the crime, and are likely to press murder charges later this week. Prosecutors are expected to seek a death sentence for the adults.
India only executes criminals in extreme cases, most recently Ajmal Kasab, the only gunmen to survive a 2008 commando-style onslaught in Mumbai, who was hanged in November. (Reporting by Aditya Kalra, Satarupa Bhattacharjya, Arup Roychoudhury, Suchitra Mohanty and Rajesh Kumar Singh; Writing by Frank Jack Daniel)