UPDATE 2-Central African Republic rebels enter capital

* Rebels clash with army inside capital

* Seleka fighters head for presidential palace

* Government said South Africa promised more troops (Recasts with rebels entering the capital)

BANGUI, March 23 (Reuters) - Central African Republic rebels clashed with government forces inside the capital on Saturday and a rebel spokesman said their columns were pushing towards the presidential palace.

The Seleka rebel coalition resumed hostilities this week in the mineral-rich former French colony, vowing to topple President Francois Bozize whom it accuses of breaking a January peace agreement to integrate its fighters into the army.

A Reuters reporter in the northern suburbs of the riverside capital said Seleka rebels had driven back government forces and taken control of the neighbourhood around Bozize’s private residence. Officials have said Bozize was in the presidential palace in the town centre.

Nelson Ndjadder, a spokesman for the Seleka rebel group, said that his fighters had shot down a government military helicopter which had been harrying their columns since Friday.

“Our two columns are now heading for the presidential palace,” he told Reuters.

A senior official with a regional peacekeeping force, who asked not to be identified, confirmed that the rebels were pushing back government troops inside Bangui and had shot down the attack helicopter.

“The rebels could take Bangui this evening,” he said, adding regional peacekeepers would secure the airport. “The fighting is continuing but there is still some resistance.”

Seleka, a loose umbrella group of insurgents, fought its way to the gates of the capital late last year after accusing Bozize of failing to honour an earlier peace deal to give its fighters cash and jobs in exchange for laying down their arms.

The violence is the latest in a series of rebel incursions, clashes and coups that have plagued the landlocked nation in the heart of Africa since its independence from France in 1960.

Pretoria has sent some 400 soldiers to train Bozize’s army, joining hundreds of peacekeepers from the Central African regional bloc. Regional peacekeeping sources said the South Africans had fought alongside the Central African Republic’s army.

State radio announced late on Friday that South Africa would boost its troop presence after Bozize met his South African counterpart Jacob Zuma in Pretoria.

Captain Zamo Sithole, senior operations communications officer at South Africa’s National Defence Force said: “We are there in the CAR to protect our properties there, and our troops there.” A South African Defence Ministry spokesman declined to comment.

CAR remains among the least developed countries in the world despite rich deposits of gold, diamonds and uranium. (Additional reporting by Ange Aboa in Abidjan; Writing by Daniel Flynn; Editing by Stephen Powell)