Burundi's last remaining rebel group has dealt a blow to peace in the country Tuesday, rejecting the newly formed government's invitation to join peace talks.  But Burundi government officials say they are still determined to bring the holdout rebel group to the negotiating table.

Burundi's new president, Pierre Nkurunziza, sworn in just three weeks ago, vowed to continue seeking peace with the National Liberation Forces (FNL), a Hutu-dominated rebel group that doesn't even recognize the government's right to exist.

On Saturday, President Nkurunziza announced an eight-member commission to mediate a truce with the FNL.

The FNL's rejection of the peace offer came as no surprise. The spokesman for the rebel group, Pasteur Habimana, said in a radio broadcast Monday the government was not legitimate because, as he put it, it was imposed on the country by the international community.

Karenga Ramadhan, the spokesman for Burundi's government, says he is not discouraged.

"The only way is to go through negotiations,? said Ms. Ramadhan.  ?If they don't, of course, we still have to weigh it until the outcome of the initiative, because at this time we are talking in New York. President Pierre Nkurunziza is meeting African leaders in the presence of Mr. Kofi Annan, and we hope that the outcome of that meeting will set the pace for the opening of negotiations. And we think with the support of the regional leaders with the support of the international community and in particular the United Nations and our own pressure, the FNL cannot afford to continue rejecting negotiations."

Other rebel groups in Burundi's 12-year civil war have joined the transitional government under a United Nations-backed peace agreement.

Burundi's civil war pitted the country's ruling Tutsi minority against a Hutu majority. More than 250,000 people, mainly civilians, were killed in the conflict.