KHARTOUM, Sudan: The secretary general of a Sudanese opposition party was killed in a car crash Saturday on a highway outside the capital, dealing a blow to the party as it prepares for elections expected next year.

Abdel Nabi Ahmed, of the Umma party, was driving with his two sons south of Khartoum when the accident occurred. His sons survived.

Party officials said his death comes at a critical time for the party, with national and presidential elections expected in 2009.

Originally from Darfur, Ahmed, 58, was seen as a figure capable of rallying the people of the vast western region of Sudan, where rebels have been at war with government forces and allied militiamen since 2003.

The party has captured Darfur votes in past national elections. The party's leader, al-Sadek al-Mahdi, was the last democratically elected prime minister. He was unseated in 1989 by current President Omar al-Bashir in a military coup.

The Umma party has since splintered into a number of factions.

Party leader al-Mahdi was not in Sudan Saturday, but was expected to return for Ahmed's funeral Sunday, said Sara Nugdallah, a senior party member.

Mourners began to gather Saturday outside the party's headquarters in Omdurman, the twin city of Khartoum, Sudan's capital.