KHARTOUM, Apr 15, 2005 -- Robert Zoellick, US deputy secretary of state, on Thursday put pressure on the Sudanese government to stop the violence in Darfur but backed away from the Bush administration's assertion that the mass killings and village burning amounted to genocide.

Mr Zoellick is the first senior US official to travel to Khartoum since Congress was told last September that a long US inquiry had determined the Sudanese government and allied janjaweed militia were responsible for genocide in the western region.

But at a press conference after meeting Ali Osman Taha, vice-president, Mr Zoellick was clearly unwilling to repeat that assertion. "I don't want to get into a debate over terminology," he said, when asked if the US believed genocide was still being committed in Darfur against mostly African villagers by Arab militia and their government backers.

He said it was Colin Powell, the former secretary of state, who had "made the point" in his testimony to Congress.

Nonetheless, Mr Zoellick did speak of "crimes against humanity", in line with the findings of a United Nations commission of inquiry. He said he had emphasised to the Sudanese government the need for accountability through sanctions and legal processes, referring to the UN resolution that sent the issue of Darfur to the International Criminal Court.

Mr Zoellick, who is to make a quick visit to Darfur today, also proposed to the government that it start using its own courts and make the process transparent.

Estimates of the numbers of dead from the conflict vary hugely. The Bush administration says 60,000-160,000 people have died from fighting, disease and famine.

Aid organisations say that the death toll is closer to 300,000.

Whether to describe the violence in Darfur as genocide became a heated issue in Washington last year. Mr Powell was under intense domestic pressure, notably from Christian lobby groups, to reach the genocide definition.