Militants in Nigeria's oil-rich Niger Delta region say they have destroyed an oil installation a day after declaring they were "at war" with the military. A flow station belonging to Shell in Alakiri, in Rivers State, was attacked in the early hours of the morning, a military spokesman confirmed. The Movement for the Emancipation of the Niger Delta (Mend) said they killed several soldiers and workers inside. But the military said they had suffered no casualties. In an e-mail to journalists, Mend said they would not be taking hostages in their new campaign. "The foolhardy workers and soldiers who did not head our warning perished inside the station," Mend spokesman Jomo Gbomo said. Military spokesman Lt Col Sagir Musa said that was "disinformation". "There was no casualty on the military side, the situation is being closely monitored and is under control," he said. 'Oil war' On Sunday, militants said they had "declared war" on the government after battling security forces guarding oil facilities. Mend said it was responding to attacks by the military. The military said it had repelled several Mend attacks. Both sides say their opponents suffered heavy losses. Mend's violent campaign for a bigger part of the area's oil wealth has cut Nigeria's oil output by more than 20%. Mend militants are the most publically visible of several armed groups operating in the impoverished delta region. They frequently kidnap foreign oil workers and sabotage oil installations and pipelines. The Niger Delta region is the source of most of the Nigerian government's income, yet it remains blighted by poverty and corruption. Source: BBC