Paramilitary forces in Sudan's Darfur have mutinied, the interior ministry said on Sunday, as a United States diplomat expressed concern that security in the western region is worsening.

"A small group from the Central Reserve Police started a mutiny," the ministry said in a statement carried by the official SUNA news agency.

Sudanese Interior Minister Ibrahim Mahmoud Hamed has said that the Darfur region is largely calm, despite tribal and other unrest which according to the U.N. forced almost 90,000 people to flee this month.

"The minister has affirmed (the) calmness of conditions in all Darfur states, except some looting operations carried out by the rebel movements", and attacks on commercial convoys, Hamed said, according to remarks published Thursday by the official SUNA news agency.

Sudan's air force carried out air strikes that wounded civilians in South Kordofan on Thursday, rebels said ahead of peace talks next week.

"They bombed one of the villages there," Arnu Ngutulu Lodi, spokesman for the Sudan People's Liberation Movement-North (SPLM-N), told Agence France Presse.

Seven Sudanese military officers convicted and jailed over a coup attempt walked free on Wednesday, just days after they were sentenced, an Agence France Presse reporter witnessed.

The seven converged on the home of Brigadier Mohammed Ibrahim, who had received the heaviest sentence of five years in prison.

About 35,000 people may have been affected by fighting in Sudan's southern Darfur region, but authorities have told aid agencies it is not safe for them to access the area, the U.N. said on Monday.

Residents fled after rebel attacks and "possible" air strikes around the towns of Muhagiriya and Labado, about 100 kilometers (62 miles) east of the South Darfur state capital Nyala, international peacekeepers have said.

Sudan's President Omar al-Bashir arrived in South Sudan Friday for the first time since his 2011 visit for the country's independence celebrations, an Agence France Presse reporter said.

South Sudanese President Salva Kiir, Bashir's former civil war foe and an ex-rebel commander, welcomed his counterpart at Juba airport.

Four members of Sudan's opposition Popular Congress Party have been released under a presidential amnesty after more than eight years in prison, the party said on Thursday.

"They have been freed today after spending 103 months in prison," said Kamal Omer, the chief of political affairs for the party led by Sudan's veteran Islamist Hassan al-Turabi.

Sudan's defense minister, who is wanted for alleged war crimes in Darfur, said on Wednesday that improving relations with South Sudan will help to "end" a decade-old rebellion in the western region.

"The implementation of the cooperation agreements with South Sudan will affect security in Darfur," Defense Minister Abdelrahim Mohammed Hussein said in a national security briefing to parliament.

Security agents confiscated the entire print run of a Sudanese daily newspaper, a senior editor said on Tuesday, adding to concerns about the role of the intelligence service in press censorship.

A member of the National Intelligence and Security Service (NISS) took all the copies of Al-Ahram Al-Youm's Tuesday edition and said they were banned from distribution, the paper's managing editor, Bokhari Bashir, told Agence France Presse.

Sudan's President Omar al-Bashir will travel to South Sudan on Friday, his office said, in a further sign of easing tensions between the two neighbors which fought along their common border last year.

"It's confirmed that President Bashir will visit Juba this Friday," Emad Sayed Ahmed, the presidential press secretary, told Agence France Presse on Tuesday.