Powell spoke before the Senate Foreign Relations Committee and blamed the government of Sudan for widespread violence that has left some 50,000 people dead. His statement came as the U.N. Security Council is preparing to meet over a new draft resolution that calls for Sudan to comply with requests to stop the violence or face sanctions on its oil industry.
Sudan produces some 320,000 barrels of oil per day, according to the Associated Press. Its main customers, China and Pakistan, are expected to oppose any call for sanctions.
"Genocide has been committed in Darfur," Powell said. "The government of Sudan and the Janjaweed bear responsibility and genocide may still be occurring."
Powell urged the African Union, a union of African countries headed by Nigerian Pres. Olusegun Obasanjo, to increase the number of its monitors in the country to assess the political and humanitarian situation, Reuters reported.
He stopped short of calling on specific action from the United States, though as a party to the United Nations' convention on genocide, the United States is required as are other nations to "undertake to prevent or punish" acts of genocide and to help "suppress" such acts.
"Call it civil war, call it ethnic cleansing, call it genocide the reality is the same: there are people in Darfur who desperately need the help of the international community," he said.
Leading up to Powell's statement Thursday, Sudanese officials opposed a ruling of genocide saying it would impede peace talks between government officials and Darfur rebels.
"It will break everything," Angelo Beda, deputy speaker of Sudan's parliament said in a Reuters report. "And the consequences will be so shameful."
Beda added that the United States was "acting like a bull in a China shop."
The United Nations, along with international humanitarian aid groups, has accused the Sudanese government of supporting the Janjaweed, an Arab militia comprised of hooded men on horseback, as part of an effort to quell an almost two-year long rebellion in Darfur. Since then the militia has carried out acts of violence against African farmers and villagers, raping, maiming and killing them in systematic attacks.
The government has denied backing the militia but has failed to disarm them or stop the widespread killing.
More than 1 million Sudanese have been displaced from their homes as part of the conflict and the U.S. Agency for International Development estimates another 300,000 could die from starvation and disease as a result.