LAGOS: Nigeria's hopes for an end to three years of violence in the oil-rich Niger Delta have been raised after an amnesty and a rebel truce, but a lasting peace is still uncertain, analysts say.

"It would be unrealistic to say this is the end of the Niger Delta's problems," Elizabeth Donnelly, Africa programme manager at the British institute Chatham House, told AFP.

The amnesty process is "a chance to implement some change" but there are "a lot of reasons to be sceptical," she said, warning there could be more "broken promises".

In view of persistent attacks from armed groups, responsible for Nigeria's oil output dropping from 2.6 million barrels a day in 2006 to around 1.7 million, Nigerian President Umaru Yar'Adua decided in June to offer an amnesty.

Thousands laid down their arms and the main rebel group, the Movement for the Emancipation of the Niger Delta (MEND), declared an indefinite ceasefire.

Since 2006 oil multinationals in Nigeria have lived to the rhythm of kidnappings and sabotages, but now are breathing a sigh of relief.

"We see the effects. There are no disruptions. There are still destructions, but this is ordinary criminality," the head of one multinational told AFP.

However, he said the authorities are not well prepared. During a recent meeting between representatives of major multinationals and Vice President Goodluck Jonathan, the latter asked for suggestions on the amnesty process.

"Clearly they want to do something, it is reassuring, but there is some improvisation involved. They should have thought about this in June when the amnesty started, not afterwards," the oil company source told AFP.

Marc-Antoine Perouse de Montclos, a researcher and Nigeria specialist, said the DDR process (disarmament, demobilisation and reinsertion) is only at the first "D" stage and not accompanied or followed by political negotiations.

"It is a matter of knowing how long before the violence starts up again", he says.

A diplomatic source in Abuja told AFP "this could be a significant first step. What is needed is a long term engagement to achieve lasting peace" and a comprehensive development strategy for the Niger Delta.

Regarding promises made by the authorities, namely to pay petrodollars directly to poor Delta communities, everyone agrees they must act fast.

"If no quick actions or results are seen on the ground, of course there's a risk people will pick up their arms again," the diplomat said.

According to Elizabeth Donnelly, "we should not forget that the reasons MEND had to exist -- frustrated and unemployed youths, availability of arms, crude oil theft, underdevelopment -- all still remain in the Niger Delta."

Joseph Evah, coordinator of an ethnic rights watchdog, sees "Nigeria sitting on a keg of gun powder because the Egbesu boys (militants) have not surrendered all their guns."

He described what they turned in during the amnesty exercise as the "tip of the iceberg."

Many observers fear the authorities have a "hidden agenda" in anticipation of the presidential and federal elections in 2011.

Montclos said the amnesty could allow for "the recruitment and arming of young people in preparation for the elections," to "eliminate" the internal opposition in the ruling People's Democratic Party.

He said these fighters are "often manipulated by the governors of oil-producing states".