Human Rights Watch on Saturday urged Nigeria to bar Sudanese President Omar al-Bashir from attending a health summit next week and demanded the war crimes-indicted leader be arrested if he visits.

Nigeria is a member of the International Criminal Court, which has charged Bashir with war crimes, genocide and crimes against humanity over the conflict in Sudan's Darfur region.

The governor of Sudan's war-torn South Kordofan state, who is wanted on war crimes charges, has been transferred to a neighboring region where fighting spread this year, the presidency said on Friday.

Ahmed Haroun's move to North Kordofan, where he will be acting governor, comes as part of changes which establish a new state of West Kordofan, presidential press secretary Emad Sayed Ahmed said in a statement.

Elite troops have been deployed in Sudan's second-largest city after days of violence among members of the security forces, as residents begin the Muslim holy month of Ramadan in fear of new clashes.

An Agence France Presse correspondent was the first from a foreign news organisation to arrive in Nyala, the capital of South Darfur state, since the worst outbreak of urban warfare in Sudan's far-west region in recent memory.

The former chief of Sudan's powerful intelligence service, who faced a possible death sentence for his alleged role in a coup plot, was freed under an amnesty on Wednesday, his lawyer said.

Salah Gosh "was released because of the amnesty given by President Bashir to all those who participated in the coup," Nabeel Adeeb told Agence France Presse.

Elite Sudanese troops have been deployed in Sudan's second-largest city after days of violence among members of the security forces, as residents begin the Muslim holy month of Ramadan in fear of new clashes.

An Agence France Presse correspondent was the first from a foreign news organization to arrive in Nyala, the capital of South Darfur state, since the worst outbreak of urban warfare in Sudan's far-west region in recent memory.

About 200 Sudanese Islamists demonstrated peacefully outside Egypt's embassy in Khartoum on Monday to support ousted Egyptian president Mohammed Morsi, an Agence France Presse photographer said.

"We are with the legal president of Egypt," read a banner carried by the group, which also waved Egyptian flags.

A suspect wanted for war crimes in Sudan's Darfur has been left wounded after an attack which reportedly killed two of his men, local sources in Nyala city said on Monday.

Ali Kushayb, a former commander of the feared Janjaweed militia, was attacked on Sunday during battles which state officials blamed on "differences" between members of the security forces.

Sudan will not carry out a threat to shut a pipeline carrying South Sudanese oil for export, after the two sides agreed last week to ease tensions, a senior ruling party official said on Sunday.

"The pipeline will not be shut," said Rabbie Abdelatti Ebaid, of the governing National Congress.

Residents of a Sudanese city ran for their lives during fresh fighting and looting on Sunday, after a worker for aid group World Vision died of wounds suffered in earlier battles.

The latest violence adds to what the United Nations says is a worsening security situation in Sudan's vast western region.

An aid worker was killed on Thursday during fighting in the largest city of Sudan's troubled Darfur region, a humanitarian source told Agence France Presse.

"One killed and three (wounded)," said the source, adding that the wounded were receiving treatment at the African Union-U.N. peacekeeping mission (UNAMID) hospital in Nyala city.