The Niger Delta Avengers, a militant group that has carried out attacks on oil facilities in Nigeria’s southern oil region, said it would only negotiate with the government if independent mediators facilitated the talks, Reuters reported.

According to the Daily Mail, the government had offered to hold talks with the group, which wants a greater share of Nigeria’s oil wealth to go to the impoverished Niger Delta region.

In a statement on its website, the Avengers said they wanted multinational oil companies operating in the country to “commit independent mediators to this proposed dialogue” to “bring about a lasting peace.” They added that “if need be we may review our earlier stance of not taking lives,” if the Avengers’ demands are not met.

One of the region’s biggest militant groups, the Movement for the Emancipation of the Niger Delta, urged the Avengers to take part in negotiations.

Meanwhile, attacks in the southern swampland have pushed country’s oil production to a 20-year low in what was until recently Africa’s biggest oil producing nation.