Calm appears to have returned to the streets of Sudan's capital, following rioting and looting that erupted at the news that one-time rebel leader, and new Sudanese vice president, John Garang died in a helicopter crash.

Sudanese authorities in Khartoum, Sudan's capital, are imposing a curfew from six in the evening to six in the morning. Earlier in the day, thousands of mostly southern Sudanese youth flooded the streets of Khartoum and started burning cars and looting shops.

Violence reportedly spread to other areas of the country. In Juba, one of southern Sudan's largest towns, Sudanese Peoples Liberation Army soldiers started ransacking Arab-owned houses and businesses, Kenya's Nation TV reported.

Vice President Garang's death and its violent aftermath are sending shockwaves through this region of Africa, dimming hopes for peace in a country that appeared to be emerging from more than two decades of civil war.

Salva Kiir Mayardit - deputy SPLA chairman and Mr. Garang's most likely successor - was quick to try to reassure those in Khartoum that Mr. Garang's death would not derail the peace deal reached between him and Sudanese President Omar el-Bashir.

"Southern Sudan and, indeed, the whole Sudan has lost its beloved son, Dr. John Garang de Mabior. The first vice president of the Republic of Sudan and the president of South Sudan was on an official visit to Uganda during the period of 29 - 30 July, 2005, when the helicopter he was traveling in crashed near South of New Kush on his return last Saturday," Mr. Kiir says. "I take this opportunity to assure the southern Sudanese, in particular, the Sudanese people, in general, that we in the SPLA leadership will continue the vision and the objectives of the Movement that Dr. John Garang de Mabior has articulated and hoped to implement."

The 60-year-old Mr. Garang was a towering figure in the SPLA rebel group. His ability to unify southern Sudan made him an essential figure in the peace process.

Under the peace deal he helped negotiate with Sudanese President Omar al-Bashir, people in southern Sudan are scheduled to vote on a referendum on whether to break away from northern Sudan after a six-year interim period.

Rumors of Mr. Garang's death began circulating late Saturday. He had not been heard from since he left a Ugandan airport in a helicopter earlier in the day. Ugandan officials confirmed Sunday the helicopter was missing, and on Monday U.N. officials confirmed that Mr. Garang, who was 60, died in the helicopter crash.

Ugandan and Sudanese authorities say Mr. Garang's helicopter tried to land in bad weather before the crash.

Mr. Garang received military training at the U.S. army base at Fort Benning, Ga, before earning a doctorate degree in agricultural economics at Iowa State University.