KIGALI, Aug 15 (Reuters) - China must stop supplying weapons to Sudan and curb ties with the country to help halt killings in the war-torn region of Darfur, activists said on Wednesday.

Olympic Dream for Darfur, a U.S.-based advocacy campaign, appealed to the Chinese government as hosts of the Olympics next year to use its influence in Sudan to boost security.

"Genocide can only stop if there's willingness (in the) international community to stop it, and for Darfur that power lies in China," said Jill Savitt, director of the Olympic Dream for Darfur.

The activists accused China of continuing to carry out oil deals with Sudan and supplying weapons to the Khartoum government, which end up in the hands of Darfur militias.

China, the biggest foreign investor in Sudan, has said its arms sales to the country are limited and abide strictly by international rules.

In the Rwandan capital on Wednesday, activists lit a torch symbolic of China's role as Olympic host nation in the Games which will be held in Beijing next August.

"This flame represents the hope we all share for an end to the violence and a safe return home," said Mia Farrow, the Hollywood actress and rights activist who is the goodwill ambassador for the U.N. Children's Fund UNICEF.

The torch will be taken to nations that have suffered genocide, and was carried past mass graves in Kigali on Wednesday, a reminder of the 1994 genocide that killed 800,000.

After Africa, the torch will travel to Armenia, Bosnia, Germany, Cambodia and Hong Kong.

International experts estimate 200,000 have died and 2.5 million driven from their homes in more than four years of violence in the remote western Sudanese region of Darfur.

"The slogan for next year's Olympics is 'One World One Dream' but that cannot be fair if there are killings in Darfur. China as a host of the Olympics should talk to their Sudanese allies to stop the killings," Savitt said.

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