Sudan's reprisal attacks worsen
Riots continue in Sudan's capital, Khartoum, despite a curfew, with Arab and southern Sudanese gangs launching a series of retaliatory attacks.
More than 800 people have been wounded and 71 killed in the violence which erupted after ex-rebel southern leader John Garang died in a helicopter crash.
Most casualties are southern Sudanese and the large military presence is struggling to contain the violence.
US envoys are to meet Garang's successor Salva Kiir, who urged calm.
He told the BBC "nobody wants war" and reiterated his commitment to the peace process.
Garang signed a deal to end 21 years of civil war in January and was sworn in as vice-president of Sudan three weeks ago.
Mr Kiir has been chosen as new leader of the former southern rebel group, the Sudan People's Liberation Movement (SPLM), and is expected also to be the country's vice-president.
Ethnic tension
The BBC's Alfred Taban in Khartoum says 19 people died on Tuesday in reprisal attacks on the outskirts of the capital, where southerners live in displacement camps.
Among those killed were at least five schoolchildren and an imam.
Security forces tried to separate those fighting, he said, but southerners accuse them of siding with the northerners, who are mainly Arabs.
Rain storms restored order on Tuesday night, but the situation is tense, he says.
News of Mr Garang's death sparked riots among southerners on the streets of Khartoum on Monday leaving 52 dead.
Mourning
Meanwhile, US envoys are to meet Mr Kiir in New Site, a southern Sudanese settlement near the scene of the crash, where former rebel fighters and civilian supporters have gathered to pay their respects to Garang.
They will also hold talks with President Omar al-Bashir and other Sudanese leaders as part of the efforts to help reinforce the peace agreement.
Garang's funeral is due to take place on Saturday in Juba, the town he chose to be the capital of the autonomous region of southern Sudan.
State media is reporting that President Bashir will be among those attending the funeral.
Garang's body will be taken to other key towns in southern Sudan to allow supporters to pay final respects before the state funeral in Juba, a spokesman announced.
On Tuesday, the United Nations Security Council urged calm.
"This is a time for the world community to come together to support Dr Garang's vision of a united and peaceful Sudan," it said.