South Sudan offered a cautious welcome Wednesday to foe Sudan's pullout of troops from the contested border region of Abyei, a year after Khartoum's army stormed the area forcing thousands to flee.

"We welcome of course the move by the Republic of Sudan... it's a sign of peace," said Information Minister Barnaba Marial Benjamin.

A British aid worker kidnapped nearly three months ago in Sudan's conflict-plagued Darfur region has been freed, the U.N.'s World Food Program said on Wednesday.

"After 86 days in captivity in the South Darfur region of Sudan, British aid worker Patrick Noonan, who was working for the U.N. World Food Program, has been released," WFP said in a statement.

Top negotiators for Sudan and South Sudan met Tuesday for their first talks since deadly border fighting last month took them to the brink of war, even as Juba accused Khartoum of fresh air strikes.

Teams from both sides are in the Ethiopian capital for African Union-led talks which were stalled by heavy clashes last month, the worst fighting since the South won independence last July.

Sudan's army will begin pulling out of the contested region of Abyei from Tuesday, as demanded by the United Nations, the army spokesman said.

"We will start tomorrow and we will invite journalists to see this redeployment," Sawarmi Khaled Saad said in a statement to reporters.

South Sudan said Monday Sudanese war planes and artillery had bombarded its territory on the eve of peace talks, as Southern officials set off to attend African Union-led negotiations in Ethiopia.

"They are bombing South Sudan, attacking South Sudan, and continuing to send armed groups to destabilize South Sudan... these are not the signs of peace," South Sudan's top negotiator Pagan Amum told reporters.

Arab League chief Nabil al-Arabi will travel to Sudan on Sunday, following a request from Khartoum for help over South Sudan's invasion of the Heglig oilfield, Arabi's deputy said.

Arabi will hold talks with President Omar al-Bashir and senior Sudanese officials, deputy Arab League chief Ahmed Ben Hilli told reporters.

South Sudan is ready to resume negotiations with Sudan, Juba's lead negotiator said late Tuesday on the eve of a United Nations date to restart talks, but also accused Khartoum of not being willing to meet.

"As per the timeline set out in the U.N. Security Council resolution, the parties are supposed to have resumed negotiations by the 16th of May, and we have not received any invite," negotiator Pagan Amum told AFP.

U.N. leader Ban Ki-moon has called on Sudan to move its troops out of the disputed territory of Abyei after rival South Sudan withdrew its security forces.

Ban called on both governments to fall in line with a U.N. Security Council deadline to start talks on all their disputes, said U.N. spokesman Martin Nesirky in a statement released late Saturday.

The first group of ethnic South Sudanese among up to 15,000 camped in crowded conditions in Sudan were to begin their journey home on Saturday, the International Organization for Migration said.

About 400 people will be brought to Khartoum by bus from the way-station of Kosti, about 300 kilometers (190 miles) south of the capital, ahead of a major airlift early on Sunday, IOM Sudan chief Jill Helke said.

Sudanese air strikes on foe South Sudan could amount to international crimes, the U.N. rights chief warned Friday, adding that she was "saddened and outraged" at bombing raids that broke a U.N. ceasefire order.

"Deliberate or reckless attacks on civilian areas can, depending on the circumstances, amount to an international crime," U.N. High Commissioner for Human Rights Navi Pillay told reporters.