A U.N. peacekeeper was wounded Monday in an ambush against a patrol in southeast Darfur amid heavy tribal fighting in the restive Sudanese region, the United Nations said.

Unidentified assailants launched the assault against a patrol from the African Union-United Nations Mission in Darfur (UNAMID) in Ed Daein, the capital of East Darfur state, according to U.N. deputy spokesman Eduardo del Buey.

Sudan on Monday postponed its deadline for the closure of the economically vital pipeline network carrying South Sudanese oil until next month.

The period "has been extended for another two weeks that ends on September 6," the official SUNA news agency said in a brief SMS dispatch which gave no details on what was the second such postponement.

The number of people affected by this month's flooding in Sudan has climbed to around 150,000 and is expected to rise further, the United Nations said on Monday.

More than half the victims, 84,000, are in the area around the capital Khartoum, said the U.N.'s Office for the Coordination of Humanitarian Affairs (OCHA).

Behind the brick walls of the Mycetoma Research Centre trying to unravel the mysteries of the infection is a rare story of medical success in impoverished Sudan.

With bandages on their swollen, deformed feet, patients from across the vast country arrive at the spotless facility set in a garden in the southern Khartoum district of Soba.

Flooding has killed 36 people in a region north of Sudan's capital Khartoum, official radio said on Sunday.

"Thirty-six people were killed in Nile state and 5,000 houses were destroyed because of heavy rain and floods," Radio Omdurman reported.

Four people have been killed by an unexploded ordnance (UXO) blast in Sudan's South Kordofan, the U.N. said on Saturday, in the latest such case after heavy fighting in the area.

"In Dilling, four people were killed when a UXO exploded while they were farming," the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said in its weekly bulletin.

France on Wednesday condemned the "unjustified" expulsion of 20 U.N. refugee agency staff from Sudan's Darfur region, calling on Khartoum to renew their permits immediately.

A foreign ministry spokesman said the move would hamper the ability of the United Nations High Commissioner for Refugees (UNHCR) to provide aid to the two million displaced people in Darfur, 1.2 million of whom were living in camps.

Heavy rains and flash floods in Khartoum and other parts of Sudan have killed 11 people and affected almost 100,000 in the past week, the United Nations said on Tuesday.

Giving the first official figures for the impact of the flooding, which began on August 1, the U.N.'s Office for the Coordination of Humanitarian Affairs said the capital and Nile state to its north were the worst hit, but that five other states were also inundated.

A Sudanese soldier was killed on Monday in a border clash with South Sudanese forces in Sudan's main oil-producing region, the military in Khartoum said.

"A patrol from South Sudan crossed the border in the Heglig area ... and clashed with a Sudanese patrol," Sudan's army spokesman, Sawarmi Khaled Saad, said in a statement late Monday.

Sudan air-dropped aid on Sunday to thousands of people affected by flooding caused by heavy rains in the Khartoum area, state-linked media reported.

Water 1.5 meters deep (five feet) covered roads in the east of the capital, the official SUNA news agency reported.