The Nigerian Government is talking to militants in the Niger Delta in a bid to end a wave of attacks on oil and gas facilities.
The move comes after ongoing attacks have cut oil production by 700,000 barrels a day.
But the Niger Delta Avengers (NDA) said it was not aware of any talks.
It said there would be no dialogue without involving the international community.
President Muhammadu Buhari said in a statement the government was using oil companies and security to talk to the militants “to find a lasting solution to insecurity in the region” and also said a review was being carried out for an amnesty programme for former militants which offers cash and job training.
The government had previously cut the scheme’s budget by two-thirds.
Buhari said: “We understand their feelings. We are studying the instruments of the amnesty. We have to secure the enivronment, otherwise investment will not come.”
Last month, government officials had said a one-month ceasefire had been agreed with the Niger Delta Avengers.
In a statement the group said it was not aware of any peace talk, adding: “President Buhari…is not sincere to the Nigeria people and their foreign allies.”
Militants have said they want a greater share of Nigeria’s oil wealth to help regenerate the Niger region.