UPDATE 1-Niger Delta militants reject renewed amnesty offer

* Yar'Adua says amnesty offer to militants still on table

* Main militant group rejects offer to lay down weapons

* Five-day lull in fighting in Niger Delta

(Adds reaction from militant group, paragraphs 5-6)

By Felix Onuah

ABUJA, May 29 (Reuters) - Nigerian President Umaru Yar'Adua renewed on Friday his offer for amnesty to militants in the Niger Delta, two weeks after the military launched its biggest offensive in years, but the rebels said 'no'.

Yar'Adua initially said in April he was ready to grant amnesty to gunmen in the Niger Delta if they agreed to lay down their weapons, but the main militant group dismissed the offer as mere words. [ID:nL2733295]

"Our offer of amnesty to militants in the region who lay down their arms remains on the table," the president said in a speech commemorating Nigeria's Democracy Day.

"I urge them to avail themselves of this offer and join hands with us and their peaceful and law-abiding compatriots to develop the Niger Delta for the benefit of its people."