BANGUI, Central African Republic (AFP) - The African Union (AU) called Wednesday for more troops to help stabilise the conflict-torn Central African Republic, which remains tense as its transitional parliament prepares to elect a new interim president.

As lawmakers struggled to reach agreement on the rules for the Saturday vote - raising the prospect of a delay - an African Union official told leaders from the continent's Great Lakes region that the AU-backed MISCA force needed more troops.

The force, which currently has 4,400 soldiers but was meant to have up to 6,000, struggled to contain the country's descent into a sectarian bloodbath after a rebel coalition called Seleka installed its leader, Mr Michel Djotodia, as the majority-Christian country's first Muslim president in March.

"The AU calls on your authority to provide the means for MISCA... to comfortably pursue its mandate," AU special representative for the Great Lakes Boubacar Diarra told a summit in Angola, urging the leaders present to help "definitively stabilise the situation" in the Central African Republic.

However the leaders ended their meeting without reaching a firm decision on deploying more troops.

Angolan President Jose Eduardo dos Santos, whose country is currently head of the 12-nation International Conference on the Great Lakes Region (ICGLR), said emphasis should be on the strengthening of state institutions in the strife-torn country.

"Angola ... will focus its assistance on the humanitarian side to support the peace process and transition to democracy," said Mr Dos Santos.

Meanwhile in Bangui, the country's transitional parliament ended its session on Wednesday without finalising the rules for its upcoming vote on a new interim president to replace Mr Djotodia, who stepped down on Friday under international pressure over his failure to rein in his ex-rebels and stem the escalating violence.

"That risks delaying the timeline," said Ms Lea Kouyassoum Doumta, the transitional ruling body's vice president. "The election could be held Sunday or Monday."

Who can be president?

One of the rules under consideration would bar anyone from running who has been in a rebel group or militia in the past 20 years.

"That's a lot of people in the Central African Republic," said one lawmaker. The poor, landlocked country of 4.6 million people has a long history of coups and rebellions since gaining independence from France in 1960.

But the main stumbling block for the 135 lawmakers was whether to acquiesce to international pressure to abstain from standing as candidates themselves.

Mr Noel Essongo, representative for a committee on the crisis that represents France, the United Nations and the Economic Community of Central African States (ECCAS), told lawmakers to step aside.

"The international community calls on the National Transitional Council not to act as judge and jury in an essential election for the strategic continuation of the transition," he said.

"We invite the National Transitional Council to contribute to peaceful and transparent elections by adopting consensual criteria and excluding all its members from running."

Speaking on condition of anonymity, one member of the transitional parliament said: "International donors and ECCAS are making demands. They give us 'opinions', but we have the impression they are twisting our arms."

Current interim leader Alexandre-Ferdinand Nguendet, the speaker of parliament, had seemed to be in campaign mode in recent days, but said on Wednesday he would not run for interim president, confirming reports from aides and a Western diplomatic source.

Mr Nguendet said he wanted to "promote a climate of calm" for the vote.

After Mr Djotodia seized power, his Seleka fighters' looting, killing and raping sparked revenge attacks from Christian militias set up to defend against them. The violence claimed 1,000 lives in the last month alone and uprooted almost a million people.

There have been signs of improved security in Bangui in recent days, thanks in part to the massive presence of MISCA and 1,600-troop French force Sangaris.

But residents said the violence continued in some areas.

"The killings are still going on quietly in our neighbourhoods," said one.