Thousands of militants have given up their weapons under an amnesty

Nigeria's main militant group in the oil-producing Niger delta has described peace talks with President Umaru Yar'Adua as promising.

A spokesman for the Mend group said the meeting signalled the beginning of "serious, meaningful dialogue". The government said it was "fruitful".

Attacks by the militant group in the Delta region cost Nigeria around $1bn (£598m) a month in lost revenue.

A ceasefire was declared three weeks ago to allow talks to go ahead.

President Yar'Adua's spokesman Olusegun Adeniyi said the discussions on Saturday were "frank and fruitful".

Nobel-prize winning Nigerian writer and political activist, Wole Soyinka, also took part in the talks.

Thousands of militants have given up their weapons in an amnesty deal offered by Mr Yar'Adua in June.

In return they have been promised education and jobs.

A three-month respite from the violence has brought back some oil and gas production, but sceptics fear the former fighters could resume violence if they do not quickly find work.

According to Reuters, security experts say some former militants have reverted to their old ways by tapping into oil pipelines and selling it on the international market.