Thousands of activists have gathered in front of the U.S. Capitol building in Washington to pressure the international community to end the violence in Sudan's western Darfur region.
The rally is among almost 20 being held in cities around the nation on Sunday under the banner "Save Darfur: Rally to Stop Genocide."
Religious leaders, politicians and sports figures attended the Washington protest, saying they stand together with victims of suffering in Darfur. Holocaust survivor Elie Wiesel called on world leaders to take risks, if necessary, to stop the massacre.
Oscar-winning actor George Clooney, who recently visited the region, was also expected to take part in the protest.
U.S. Secretary of State Condoleezza Rice told U.S. television audiences Sunday (on CNN's Late Edition) that the U.S. has been actively pushing for a peace settlement in Darfur, but needs more help from the international community.
President Bush has called on Sudan's government to do more to protect civilians in Darfur, since the start of fighting between rebels and government-backed forces three years ago.
Last week, he signed an order freezing the assets of four Sudanese blamed for atrocities in Darfur.
Tens of thousands of people have died in the violence, and more than two million have lost their homes.