The International Criminal Court on Wednesday urged U.S. authorities to arrest Sudanese President Omar al-Bashir, an indicted war crimes suspect, should he travel to New York for a U.N. summit.

The court has asked "the competent U.S. authorities to arrest Omar al-Bashir and surrender him to the court, in the event he enters their territory," it said in a statement.

Two Iranian warships have entered Sudan's territorial waters and were heading to dock for "routine" fueling, a spokesman of Sudanese army said on Wednesday.

"Two Iranian ships have entered our territorial waters, one of them is a destroyer and the other is a supplies vessel," Colonel Sawarmi Khaled Saad told Agence France Presse.

Clashes between rival tribes in Sudan's western region of Darfur on Wednesday killed at least 20 people despite a peace deal agreed last month, a tribal chief said.

Sheikh Merdes of the Maaliya tribe told Agence France Presse by telephone that "clashes broke out today when a group from the Rezeigat tribe attacked us in the Bakhit region" some 70 kilometers (45 miles) east of East Darfur capital Ed Daein.

U.N. leader Ban Ki-moon wants Sudan's President Omar al-Bashir to answer war crimes charges, a spokesman said Tuesday as controversy mounted over Bashir's bid to attend a U.N. summit next week.

Bashir, who is wanted by the International Criminal Court for genocide in Darfur, has embarrassed the U.S. government and United Nations by seeking a visa to enter the United States to attend the annual U.N. General Assembly next week.

Khartoum insisted Tuesday that Washington is obliged to grant Sudanese President Omar al-Bashir a visa to attend the U.N. General Assembly despite a warrant for his arrest on war crimes charges.

The Sudanese foreign ministry said that as host nation of U.N. headquarters in New York, the United States had no choice but to facilitate his attendance as head of state of a member nation.

Sudan and South Sudan averted Tuesday a shutdown of economically vital oil flows and again pledged to implement economic and security pacts that have twice failed to take effect.

At the close of a one-day summit with his South Sudanese counterpart, Salva Kiir, Sudanese President Omar Bashir said the South's oil will continue to move through Sudan for export on the Red Sea.

Peacekeepers came under fire in Sudan's Darfur region while they searched for colleagues missing in a flood, the mission said Thursday, reporting the third attack this month against Blue Helmets.

The attack by "unknown armed men" happened on Tuesday about seven kilometers (four miles) northeast of Misterei, a West Darfur town near the border with Chad, said Rania Abdulrahman, a media officer with the African Union-United Nations Mission in Darfur (UNAMID).

Three peacekeepers have been shot and wounded in Sudan's East Darfur region, the mission said on Tuesday, the second attack this month against Blue Helmets in the same area.

The incident occurred on Monday in the region where, according to the U.N., fighting between two Arab tribes this month killed 190 people.

The impact of Sudan's floods has widened, the United Nations said on Tuesday, with more than half a million people affected by this month's inundations.

"An estimated 574,540 people have been affected," the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said, citing government figures.

Four peacekeepers are missing in Sudan's troubled Darfur region after a flash flood hit while they escorted an aid mission, UNAMID said on Monday.

"A UNAMID rescue team from El Geneina, West Darfur, found two peacekeepers alive while a search is ongoing to locate the other four," an official of the African Union-United Nations Mission (UNAMID) told Agence France Presse.