Central African Republic rebels captured two more towns overnight, just days before talks were due to open on the crisis in the impoverished country, an official said Saturday.
"The rebels took two towns near Bambari," a town already under the control of the Seleka rebel coalition, Territorial Administration Minister Josue Binoua told AFP.
"This shows their intent to wage war even during negotiations," he said.
There was no immediate reaction from the rebels themselves to the claim.
The comments came just days before the central African regional bloc CEEAC hopes to start hosting talks between the rebels and President Francois Bozize in an effort to solve the nearly month-long crisis in the mineral-rich but impoverished and unstable country.
The rebels threw those plans into doubt on Friday when they contradicted claims by CEEAC officials that they had agreed to the talks due to begin in Gabon's capital Libreville on Tuesday, saying they had not been informed of the initiative by the Economic Community of Central African States.
On Saturday, Binoua said the talks, which have the support of the UN Security Council and the United States, would proceed as planned.
"There will be three delegations of 15 members each - the government, rebels and opposition," he said.
Bozize will head the government delegation while the opposition's will be headed by the lawyer Nicolas Tiangaye, he added.
The rebels, who charge that Bozize has not abided by terms of earlier peace deals, launched an offensive on December 10 in the north and easily overran an ill-equipped and poorly trained army, marching across a large part of the country before halting their push within striking distance of the capital Bangui, in the south-west.
Rebel troops were stationed at Sibut, some 160 kilometres from the capital.
Also Saturday, the organiser of youth groups who have been manning roadblocks at night in Bangui said they would be largely replaced by CEEAC "vigilance committees".
The youth groups known as Kokora (blood arrow) have come under criticism from the opposition and ordinary Bangui residents who say they increase rather than ease insecurity in the capital.
Their coordinator Levy Yakete said the CEEAC force would patrol the city's main arteries to enforce a dusk-to-dawn curfew.
Kokora will continue to operate in the suburbs, he said, dismissing accusations that some of the youths were involved in extortion and were armed with machetes.
"We are fortunate to be prepared" if the rebels enter the city, he said.
Unrest in the landlocked equatorial country has alarmed the country's neighbours and the international community, with the UN Security Council twice calling on Seleka to halt its offensive and engage in peace talks.
"The Security Council reiterated their demand that the Seleka coalition of armed groups cease all hostilities, withdraw from seized cities, and cease attempts to advance further," said a statement released by the 15-nation body on Friday.
Binoua charged on Saturday that the seizure of two more towns was "screaming proof" that the rebels could not be trusted.
Central African nations have begun sending reinforcements to Damara, the last major town between the rebels and the capital, to bolster the army against the rebels.
The regional troops are fighting under the banner of the multinational African force FOMAC, which CEEAC launched in 2008 in a bid to stabilise the coup- and rebellion-prone country.
Northern neighbour Chad, whose President Idriss Deby is an ally of Bozize, has contributed most of the troops to the force, which is due to reach its full strength of 760 by the end of the week.
The violence in the country has affected more than 300,000 children, including through recruitment as child soldiers, family separation, sexual violence and forced displacement, UNICEF has said.
The Central African Republic, with a population of about five million, is notorious for unrest including coups, army mutinies and rebellions.
Bozize himself took power in a coup in 2003 and has since been twice elected into office.