Preparations for a semi-annual African Union summit are being overshadowed by Libyan leader Moammar Gaddafi's attempt to overturn the tradition of a rotating chairmanship and to remain as AU chief.

Senior African diplomats gathering for the continental summit in Ethiopia's capital say Colonel Gadhafi is waging a well-financed campaign to keep his post as African Union chairman.  The issue will be decided in a closed session of AU heads of state at the opening summit session Sunday.

By tradition, the chairmanship is awarded by geographical rotation among Africa's five regions.  Last year, the northern African countries nominated Mr. Gadhafi.

This year it is southern Africa's turn, and the countries of the region have nominated Malawi's President Bingu wa Mutarika.  A Malawian diplomat expressed confidence the nomination would be approved.

But the head of the organization's executive arm, Commission Chairman Jean Ping, says rules governing the selection process are loosely defined.  He spoke in French.

He says the choice of who will preside over the union for the next year is solely up to the heads of state.  They make the rules, and if they want, they can modify them.

Ping told reporters the principle of geographic rotation could be overturned.   He says the rotation rule has been followed in the past, but whether it would be followed this time, he does not know.

Mr. Gadhafi, who led a military coup that took power in Libya more than 40 years ago, has said one year is not enough to carry out his plans for African integration.  He is pushing for creation of an African Union Authority that would have far broader powers than the current Commission, and wants to form a continental defense force under a single command.

Attempts to contact Libyan diplomats for this story were unsuccessful.

Several of Africa's larger and more powerful countries are known to oppose both the pace of Mr. Gadhafi's integration plan and his effort to stay on as AU chief.

A number of heads of state were said to have taken offense last year when, after being elected chairman, the eccentric Libyan leader declared himself 'King of Africa'.

But few question his ability to get what he wants.  He is said to have won the backing of several of Africa's weaker and poorer states, some of which have received Libyan financial aid.

Diplomats and experts on AU procedures say Mr. Gadhafi would probably need the support of two-thirds of the heads of state attending the summit to retain the chairmanship.  But based on past attendance, it is possible fewer than half of the body's 53 heads of state will be present at Sunday's closed-door session.

Western diplomats, whose countries finance one-third of the AU budget, say allowing the Libyan strongman to stay on as chairman would hurt the union's effort to portray itself as a champion of democratic ideals.  They say it may also force donors to reconsider their support.

Mr. Gadhafi's three immediate predecessors as chairman had all been democratically elected heads of state, helping the continental body to rid itself of its old reputation as a club for dictators.