John Negroponte, the US deputy secretary of state, added: "We are prepared to put sanctions.
"The notion of sanctions is not limited to the [Khartoum] government alone."
On Thursday, Ahmed Abdel Shafi, head of the Sudan Liberation Movement - a major Darfur rebel group - called for the Tripoli talks to be delayed, saying a ceasefire must first take hold.
"Genocide is a crime against humanity as a whole, not just against it's immediate targets. It therefore falls on the world at large to act."
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The African Union (AU) and the United Nations (UN), which co-chaired Friday's talks, also appealed for support to ensure the speedy deployment of a 26,000-strong joint AU-UN force to take over peacekeeping from about 6,000 under-equipped and under-funded AU troops.
The UN has warned that the force, which Sudan insists on being predominantly African, will not be effective without contributions from non-African countries.
African governments have already objected to non-African infantry soldiers being involved in the force, which could be deployed later this year.
"Our view is that there are forces that are non-African that could be helpful to the enabling of the creation of this force, whether it has to do with logistical support, helicopter transport, mechanical assistance," Negroponte said.
"We don't think Sudan has anything to be afraid of."
Earlier on Friday the chief prosecutor of the International Criminal Court (ICC) urged world leaders to "break their silence" and press the Sudanese government to arrest one of its ministers for alleged war crimes.
The comments by Luis Moreno-Ocampo, the ICC prosecutor, came ahead of a high-level UN meeting on Darfur on Friday.
Moreno-Ocampo has called for the arrest of Ahmed Harun, Sudan's humanitarian affairs minister, who faces charges of war crimes and crimes against humanity.
He said he was concerned that silence by world leaders "has been understood in Khartoum as a weakening of international resolve".