The militants said they were opposed to a new proposal by the Nigerian government.
Hundreds of former militants staged a violent protest in Yenagoa, the Bayelsa State capital, on Wednesday, smashing cars ad harassing passersby, to complain against new terms they have been offered under the federal government-run amnesty program.
News site, Sahara Reporters, reports that the ex-fighters, who enjoy monthly government allowances, smashed car windscreens, and looted shops, injuring at least one person.
Trouble reportedly started after a government authorized verification exercise announced that ex-militants would be entitled to one amnesty training slot for every 15 guns handed over by a militant camp.
The ex-militants insist that every member who surrendered a weapon be given a slot on the programme.
The demonstration was quelled after hours by operatives of the Joint Taskforce, JTF, anti-riot policemen, officials of the State Security Service and the Nigerian Security and Civil Defense Corps, the website reports.
A spokesman for the Presidential Amnesty Office, Daniel Alabrah, was quoted as condemning the violence, saying it was uncalled for since the Inter-Security Agency carrying out the verification would only recommend number of slots to the Amnesty Office.
One ex-militant, Tonye Bobo, quoted by the website rejected the proposal to offer one training slot per 15 guns turned in.
"The federal government should abide by the agreement reached between [the] late President Umaru Yar'Adua and the ex-militant leaders. The proposed 15 guns to one slot won't be acceptable to us," Mr. Bobo was quoted as saying.
The amnesty programme launched by Mr. Yar'Adua, successfully ended years of unrest in the oil rich region, raising oil production levels that had once plummeted badly.
Fighters, who surrendered weapons have since remained on monthly allowances and have been put on training amid allegations the programme has been abused and used as a cover for stealing money.