Africa News Tonight: U.S. officials say Sudan's warring parties signed a commitment late yesterday on guidelines for allowing humanitarian assistance but did not agree to a cease-fire. A war of words is brewing between the U.S. and South Africa after the American ambassador said he would "bet his life" on U.S. intelligence that South African weapons were loaded onto a Russian vessel when it docked at a Cape Town naval base in December. And, voters in the conservative West African state of Mauritania head to the polls tomorrow for legislative and local elections that will serve as a key test ahead of presidential elections next year. For this and more, stay tuned to Africa News Tonight!