* President says will step aside in 2016
* Rebels balk at peace proposals
* Regional leaders sending more troops
Central African Republic President Francois Bozize on Tuesday urged rebels threatening to enter the capital to lay down their arms and allow him to complete his term.
Fighters encamped within 75 km (45 miles) of the capital Bangui accuse Bozize of reneging on a 2007 deal meant to provide money and jobs for former rebels, and insurgent leaders are now split over whether to accept an offer of new talks.
The rebellion poses the biggest threat yet to Bozize's nearly 10 years in charge of the former French colony - one of the world's poorest nations despite its rich deposits of uranium, gold and diamonds.
"I repeat that I will not be a candidate in the 2016 election, so let me finish my mandate, I only have three years left," Bozize said in a New Year's Day address broadcast on state radio in the country's Sango language.
Bozize also admonished his national army for a string of defeats during the Seleka rebels' three-week assault, and thanked troops from neighbouring Chad for reinforcing.
"The army has not played its role. Without the Chadian army we would no longer be here to express ourselves," he said.
Bozize came to power in a 2003 rebellion and has depended on foreign military aid, including from former colonial ruler France, to ward off a succession of rebel assaults.
France said it will not defend Bozize's government this time, and has instead urged Bozize, the rebels, and the country's opposition to seek a negotiated solution.
That appeared to take a hit on Monday when rebel spokesman Eric Massi said the group had "nothing to negotiate" and accused Bozize of executing dissidents in recent days.
Another official for the rebels said on Monday Seleka leaders were divided over whether to accept peace talks, with some factions ready to lay down their weapons.
Regional leaders have agreed to send 360 extra troops to shore up CAR's army this week - adding to a more than 500-strong regional force made up mostly of Chadian troops.
Chad President Idriss Deby, who is also head of the Economic Community of Central African States, warned rebels on Monday not to advance beyond Damara, a government-held town 75 km north of Bangui and the last buffer before the capital.
The rebels meanwhile have called on CAR and regional forces backing them to switch sides and turn on Bozize.
The rebels' rapid onslaught highlights instability in a country at the heart of one of Africa's most turbulent and underdeveloped regions.
Central African Republic is one of a number of countries where U.S. Special Forces are helping local soldiers track down the Lord's Resistance Army, a rebel group which has killed thousands of civilians across four nations.
Some 1,200 French citizens live in CAR, and France has a 600-strong force in the country which it says it is using to protect its nationals and not to defend Bozize's government.