GENEVA: Thousands of Sikhs from across the globe rallied Friday at the UN's Geneva base, demanding an international investigation of a deadly wave of violence against their community in India in 1984.

Sikh activists say the killings 29 years ago were state-sponsored genocide, while India blames them on communal rioting.

Organisers told AFP they had mustered 10,000 Sikhs from Europe, North America, India, Hong Kong and Australia, while police put the figure at 4,000.

Earlier Friday, members of the New York-based group Sikhs for Justice submitted what they said was a million-signature petition to the UN human rights office, where they held talks with officials.

“The reason we are petitioning the UN to investigate the killing of Sikhs in November 1984 is that we believe the truth has not been told to the world,”Canadian-born Jatinder Singh Grewal, policy director at Sikhs For Justice, told AFP.

“What happened in November 1984 was a systematic and deliberate attempt to kill a religious minority. It happened with the complicity of the government and, in many documented cases, with the participation of the government,” he added.

Thousands of Sikhs died in an orgy of violence that erupted after prime minister Indira Gandhi was assassinated by her Sikh bodyguards in retaliation for ordering a raid on the faith's holiest temple to crush a separatist revolt.

Indian diplomats in Geneva declined to comment on the petition, but said their country's position on the killings was well-known and the issue had been handled by India's justice system.

India acknowledges that 3,000 Sikhs died in New Delhi from November 1 to 3, 1984, in what it says were communal riots.

But Sikh activists claim evidence which they continue to gather shows the killings were nationwide and that the toll was over 30,000.

They say the violence, which included countless gang rapes and drove 300,000 Sikhs from their homes -- was anything but spontaneous.

“If India has nothing in their closet, they should open the doors. But they have skeletons. The skeletons of Sikhs,” Gurpatwant Singh Pannun, Sikhs for Justice's legal adviser, told AFP.

Pannun said officials from India's ruling Congress party ran death squads, the authorities armed and transported killers, used voting lists to locate Sikhs, and state media demanded “blood for blood”. Systematic killings of a community fall under the 1948 Genocide Convention.

Pannun said India had failed in its duty to hold the perpetrators to account, making a UN probe essential. UN officials said a decision whether to open a Human Rights Council probe would not come before next year, and that it lay with the International Criminal Court to apply the genocide label.

Indira Prahst, a Canadian sociologist with Sikh and German roots, said failing to address 1984 emboldened those who killed Indian Muslims in 1992 and 2002, or Christians in 2008.

“We remember atrocities so that we do not repeat the past. And the past continues to be repeated in India through violence with impunity,” she said.