Nigeria’s Movement for the Emancipation of the Niger Delta (Mend) has threatened to call off a truce just 12 hours after it declared the 60-day ceasefire. It has accused the army of sending troops to the area where its fighters are camped.

Claiming to have information from "a very reliable source" within the Military's Joint Task Force (JTF), the Mend threatened to take up its guns again unless the army's alleged plans are scrapped.

"Barely 12 hours into our ceasefire, the military Joint Task Force has dispatched seven gunboats with heavily armed troops from Warri and are headed towards one of our camps located around the Delta/Ondo state border," a Mend statement said. "We are monitoring the armada and sincerely hope that the planned attack will be converted to a war exercise."

JTF spokesman Colonel Rabe Abubakar denied there had been any troop deployments and said the military was "implementing faithfully" the amnesty deal.

Mend started the truce on Wednesday after its leader Henry Okah wasreleased after nearly two years in jail.

It said the leader’s release was “a step towards genuine peace and prosperity if Nigeria is open to frank talks and deals sincerely with the roots issues”.

The movement promised to send aid negotiators for talks with the government. However, a precondition for the negotiations will be the withdrawal of an elite government security team from the oil rich Niger Delta.

Nigeria is the eight largest oil producer in the world but attacks on oil facilities in the country have cut output by more than 30 per cent over the last three years. Mend, who has been fighting for a greater share of the oil wealth for locals in the south, has claimed responsibility for most of the attacks.

A day before Okah’s release Mend attacked an oil depot in Lagos, far away from its usual area of operations. At least five people were killed.