At least 14 people have been killed including children and two soldiers in an attack on a train blamed on former rebel fighters south of the Congo capital Brazzaville, police said Sunday.

The attack was carried out Friday by former Ninja Nsiloulou fighters of ex-rebel chief Frederic Bintsamou, otherwise known as Pastor Ntumi, in the town of Mindouli in the Pool department.

"The ninjas killed 14 people... including children. They keep carrying out more and more terrorist acts," said police spokesman Jules Monkala Tchoumou. "It is horrific."

Recent clashes involving former ninja rebels triggered a massive exodus of locals from the area, where several villages are now completely empty.

The Ninjas fought two civil wars in the 1990s and were headed by Protestant preacher Bintsamou, who is called the Prophet by his admirers.

Bintsamou came out in favour of presidential candidate Guy-Brice Parfait Kolelas, who lost to longtime leader Denis Sassou Nguesso in elections in March, which the opposition say was marked by massive fraud.

Congo has been on edge since a constitutional referendum last October ended a two-term limit on presidential mandates, allowing the 72-year-old head of state to extend his 32 years in power.