Sudanese air force bombers targeted the only hospital in the Nuba Mountains of war-torn South Kordofan, the former Catholic bishop for the area said on Monday.

The church-run Mother of Mercy Catholic Hospital was the victim of "deliberate targeting and bombing" last Thursday and Friday, Macram Max Gassis, the Kenya-based bishop emeritus of Sudan's El Obeid Diocese said in a statement.

Hundreds of exhausted illegal migrants reached the safety of a northern Sudanese town Saturday, an Agence France Presse journalist said, after 10 died when human traffickers abandoned them in the desert.

A convoy of six Sudanese army trucks delivered the migrants to Dongola after a journey of hundreds of kilometers (miles) following their rescue on the Sudanese-Libyan frontier by troops from both countries.

A peacekeeper in Sudan's Darfur region has been freed safely after almost two months in captivity, the African Union-U.N. mission (UNAMID) there said Thursday.

The abduction of Nigerian Sergeant Awesu Soleiman had not been previously announced.

About 300 illegal immigrants abandoned by people traffickers in the scorching Sudanese-Libyan desert, where several died, will be escorted to a Sudanese town from Friday, the army said.

Army spokesman Sawarmi Khaled Saad told Agence France Presse the migrants, who were receiving medical care, would be taken by local Sudanese officials to the northern town of Dongola on the Nile River.

Peace talks between Sudan's government and rebels from South Kordofan and Blue Nile broke Thursday with little progress and amid fresh accusations of an renewed military offensive by Khartoum, rebels said.

"Our areas have been bombarded for more than 16 hours by the Sudan government and there is a huge offensive," rebel delegation leader Yasir Arman told Agence France Presse.

Nine illegal immigrants have died among some 300 abandoned by smugglers in the scorching Sudanese-Libyan desert, with the others in poor condition, Khartoum's army said Wednesday.

"They were on their way to Libya as illegal immigrants," spokesman Sawarmi Khaled Saad told Agence France Presse.

Top United Nations rights officials vowed Wednesday to do everything in their power to prevent conflict-wracked South Sudan from sliding into genocide, and warned the warring factions they would be held responsible if famine breaks out.

Firing off a damning attack against South Sudan's President Salva Kiir and rebel leader Riek Machar, the U.N.'s High Commissioner for Human Rights Navi Pillay said she was "appalled by the apparent lack of concern about the risk of famine displayed by both leaders."

U.S. Secretary of State John Kerry left late Tuesday on his first major tour of Africa focused on some of the continent's most brutal wars including the bloodshed in South Sudan. 

The trip, which will take in Ethiopia, the Democratic Republic of Congo and Angola, will seek to "encourage democratic development, promote respect for human rights, advance peace and security," State Department spokeswoman Jen Psaki has said.

The United Nations' aid chief in war-torn South Sudan called Tuesday for a month-long truce, warning that seven million people face hunger if the brutal four-month conflict continues.

"I call on all parties to the conflict in South Sudan to observe one month of tranquility this May, to stop the violence and to provide a safe environment for civilians," U.N. humanitarian coordinator for South Sudan Toby Lanzer said in a statement.

Qatar confirmed on Monday it will provide $88 million to kick-start a strategy for lasting development of Sudan's Darfur, which this year has seen its worst violence in a decade.

The commitment, signed in the North Darfur capital El Fasher, comes one year after an international donors' conference in Doha secured $3.6 billion in pledges -- mostly from cash-strapped Khartoum -- to finance the six-year Darfur Development Strategy.