Officials in Burundi said Tuesday that security forces have killed at least 18 armed bandits, raising new fears of a return to conflict in the central African nation.

A Burundian government official says troops carried out a raid on the group of gunmen on Monday after hearing reports of looting and violence in the eastern province of Cankuzo, near the Tanzanian border.

Burundi has been relatively peaceful since its Hutu rebel group, the Forces for National Liberation , laid down its arms in 2009 after 20 years of insurgency.

But the country has experienced a series of attacks following last year's elections, which were boycotted by much of the opposition.

In September, 36 people were killed when gunmen attacked a pub outside the capital of Bujumbura.

Congolese officials have suggested those attackers were likely former FNL rebels.