Nigeria's top labor union says federal officials should begin a dialogue with militants who have been attacking oil facilities in the Niger Delta region.
The call comes a day after the militants released six of the nine foreign oil workers they kidnapped from a Royal Dutch Shell facility last month.
A Nigeria Labor Congress spokesman, Owei Lakemfa, says dialogue can help resolve the militants' grievances and improve security in the area.
The federal government has shown no interest in such talks, describing the militants as terrorists. The deputy president of Nigeria's Senate, Ibrahim Mantu, says the militants must use tactics other than violence to draw attention to their plight.
The militants from the Movement for the Emancipation of the Niger Delta have been demanding greater local control over the Niger Delta's oil wealth and the release of two jailed ethnic Ijaw leaders.
Mediators in talks to free the three oil workers still held hostage say they are hopeful the three men will be released shortly.
The militants say the release of the other six workers - an American, two Egyptians, two Thais and one Filipino - will not stop them from carrying out new attacks they say will destroy Nigeria's ability to export crude oil.
Recent attacks have already cut the country's oil production an estimated 20 percent.