Around 150 armed men on horseback attacked a village in eastern Chad on Monday, killing at least four people and wounding six, two days before a presidential election, the UN refugee agency said.
A UN High Commissioner for Refugees (UNHCR) spokesman said the group that raided Dalola, not far from a camp housing Sudanese refugees, stole 1,000 head of cattle.
It was not clear whether they were rebels who have threatened to disrupt today's election, cross-border raiders from Sudan, or bandits who roam the desolate border region.
"The preliminary information we have is four dead and six wounded," UNHCR spokesman Matthew Conway said from the eastern town of Abeche.
He cited accounts given by survivors of the attack, who were treated by Italian doctors at the Goz Amer refugee camp a few kilometers from Dalola.
"We are being told that they were Janjaweed," Conway added.
The term Janjaweed, an Arabic expression which loosely means "devils on horseback," is often used to describe Sudanese government-backed Arab militias who raid villages in Sudan's Darfur region and also across the border in Chad.
However, Conway said the raid could also have been carried out by common bandits who have a history of looting settlements and stealing cattle in the huge swathes of dry savannah and desert of western Sudan and eastern Chad.
The attack took place before an election in Chad today in which President Idriss Deby is seeking re-election for a third five-year term. He faces four challengers who are either political allies or pose no real electoral threat.
Several opposition parties are boycotting the polls as a one-sided farce, and rebel groups have vowed to disrupt the voting.
"We are not going to let it take place," said a spokesman for the United Front for Change, Albissaty Saleh Allazam.
Meanwhile, the government has been tightening security ahead of the elections.
"Naturally, security forces will be reinforced," said government spokesman Hourmadji Moussa Doumgor. "It is a big country, and some small incidents to cause confusion here and there are possible, but we are taking steps to avoid that."