Washington and Britain pushed a resolution through the UN Security Council late last month demanding the deployment of 20,000 soldiers and police to help end what they described as "genocide" in the western Darfur region.
But the resolution is conditional on the Sudan government accepting the deployment, something it has steadfastly refused to do despite intensive diplomatic lobbying by Washington.
"We would certainly hope that the rest of the world would join us in pressing as hard on this issues as we have," US State Department spokesman
Sean McCormack said.
China and Russia abstained from the Security Council vote because of Khartoum's opposition to the deployment.
Mr McCormack noted that Sudan ultimately bent to the international community's will when the UN successfully brokered a 2005 peace agreement between Khartoum and rebels in the south of the country.
"The history of dealing with this Sudanese government has been that they do respond over time to concerted diplomatic pressure," he said.
"I think it is incumbent upon other member states of the United Nations to match the effort the United States has made on this issue," he said.
The combined effect of war and famine in Darfur has left up to 300,000 people dead and displaced 2.5 million in three and half years of civil war pitting the Arab-led Sudanese government and allied Islamic militias against local rebels.
Wiesel, Clooney urge action
Holocaust survivor and writer Elie Wiesel and Hollywood star George Clooney lent weight to the call for urgent action in Darfur to prevent a massacre after African Union peacekeepers leave.
The duo appeared before the UN Security Council at the invitation of US Ambassador John Bolton, who demanded that UN peacekeepers be sent to Darfur before the African force of 7,000 troops leaves on September 30.
UN officials and some Western governments fear the civilian population would be massacred by the parties in conflict without the protection of peacekeepers.
Council members who attended the meeting offered diverse proposals. French Ambassador Jean-Marc de la Sabliere said the international community should pressure Khartoum to accept UN peacekeepers.
Mr De la Sabliere said the conflict in Darfur is destabilising the African region.
"This tragedy is getting worse," he said.
Another Security Council member, Tanzanian Ambassador Augustine
Mahiga, said one immediate option is to strengthen the African force so it can remain beyond September 30, until an international force arrives. The African Union decided to pull out because it lacked logistical support and money to maintain the troops.
Clooney, who earlier this year visited Darfur refugees, invoked the past massacre of nearly one million people in Rwanda in 1994 and the killing of more than 7,000 Bosnians by Serbian forces at Srebrenica in 1995.
"The genocide in Sudan will be the first in the 21st century," he told the security council. "This genocide will be on your watch, your Rwanda, your Srebrenica."
In the Rwanda massacre, UN troops stood by without a mandate to interfere.
Wiesel denounced the lack of action to stop the daily killings and rapes in Darfur.
The presence of Wiesel and Clooney was intended to raise awareness of the humanitarian problems in Darfur, where fighting between two African groups rages despite a ceasefire signed on May 5 in Abuja, Nigeria.
"We turned to you because you, the distinguished members of the Security Council, hold their destiny in your hands," Wiesel said.
"You are supposed to speak on behalf of the highest ideals of mankind. You can stop it, there are so many ways, and you know them all."
The ethnic conflict in Darfur, a vast western Sudanese region, has killed more than 300,000 people since 2003. More than two million people have become refugees and depend on international aid.
Wiesel, a Nobel Peace laureate and director of the Elie Wiesel Foundation for Humanity, has recently set up a Darfur Commission of Nobel Laureates to examine the tragedy in Darfur.
Oscar-winning actor-director Clooney visited refugees in Darfur in April, using his celebrity clout to raise awareness about the plight of civilians caught in the ethnic conflict.