China on Monday expressed worry over the fate of two of its nationals abducted along with others from an oilfield in the war-torn Kordofan region.

An official at Beijing's Khartoum embassy said "there are two" Chinese missing, updating earlier information from Sudan's military which said one Chinese was among those kidnapped on Friday.

When not plotting military strategy to seize South Sudan's crucial oil fields, sacked vice-president turned rebel chief Riek Machar spends time reading the economic and political history "Why Nations Fail".

Cynics might argue he would do better to simply look around his basic bush camp, where mutinous soldiers and an allied ethnic militia crammed with child soldiers ready themselves to attack government forces, as a brutal four-month-long civil war in which thousands of people have already been killed intensifies.

Gunmen have kidnapped three workers including a Chinese and an Algerian from an oilfield in Sudan's West Kordofan province, the army said Saturday.

"Armed men yesterday (Friday) attacked the Kanar field in West Kordofan and abducted three workers -- a Sudanese, a Chinese and an Algerian," spokesman Sawarmi Khaled Saad told Agence France Presse.

The International Criminal Court on Wednesday postponed until further notice the war crimes trial of Darfur rebel leader Abdallah Banda, blaming "logistic difficulties" for the hold-up.

"Today the trial chamber decided to vacate the date of May 5, initially scheduled for the opening of the trial... of Abdallah Banda," the Hague-based court said in a statement.

Up to 1,000 refugees from war-torn South Sudan are fleeing to Ethiopia each day, many of them on the brink of death, the U.N. said Tuesday.

A massive 95 percent of the arrivals are also women and children, added the U.N., citing witnesses saying that both boys and men have been forcibly recruited by armed men or killed along the way.

The United States Thursday criticized Sudan's expulsion of a top U.N. official, saying it was part of a "troubling pattern" against foreign aid workers.

Pamela DeLargy, an American who headed the U.N. Population Fund (UNFPA) office in Sudan, "was asked to leave," Khartoum's foreign ministry spokesman Abubakr al-Siddiq told Agence France Presse.

Instability in Sudan's Darfur region has prevented top U.N. officers and European ambassadors from visiting a camp where thousands have fled the worst fighting in a decade, officials said Thursday.

Sudan has expelled the country chief of a United Nations agency and accused her of interfering in domestic affairs, the foreign ministry said on Wednesday.

The incident is the latest involving foreign aid workers in the restive African nation where millions need humanitarian assistance.

Two people have been killed by ordnance left behind in a Sudanese town where thousands of people are returning after rebel-government fighting last year, the United Nations said on Saturday.

They are the latest casualties from unexploded ordnance (UXO) in South Kordofan.

There is a danger the international community will ignore Sudan's "astonishing" aid needs, just as the situation in parts of the country deteriorates, a British aid official said Wednesday.

"The numbers are truly astonishing," said Cate Turton, of Britain's Department for International Development.