By Austin Ekeinde
PORT HARCOURT, Nigeria (Reuters) - Nigerian militants threatened on Wednesday to broaden their "oil war" to offshore oilfields, after attacking another Shell-operated oil flow station in the Niger Delta.
The Movement for the Emancipation of the Niger Delta (MEND), responsible for attacks that have cut a fifth of OPEC member Nigeria's oil output, said it would launch attacks outside Rivers state for the first time since clashes began on Saturday.
The heaviest clashes between militants and security forces in more than two years have spread to about 10 villages, but have remained in Rivers state, home to oil city Port Harcourt.
"After Rivers, the hurricane will be heading to the neighbouring states in the Niger Delta," the group said in an e-mailed statement.
Some security forces in the oil industry estimate more than 100 people may have been killed in recent clashes.
Militants have bombed pipelines, platforms, gas plants and oilfields, halting up to 115,000 barrels per day of oil production in the last five days, government officials said.
Nigeria's oil is popular in the United States and Europe because it is easily refined into gasoline, diesel and other crude products.
Oil markets have largely shrugged off Nigeria's violence, focusing more on the credit crisis on the global economy. Prices traded at around $94 a barrel on Wednesday.
MEND, which says it is fighting for more local control of the impoverished region's oil wealth, attacked Shell's Orubiri flow station late Tuesday with help from the Niger Delta Volunteer Force, another militant group in the region.
"It is feared the facility may have caught fire due to intense, sporadic gunshots and massive dynamite and bomb explosions," said Lieutenant Colonel Sagir Musa, spokesman for the military task force in Rivers state.
Musa said no soldiers were killed in the attack.
Militants said their next targets would be major offshore oilfields.
"Soldiers and oil workers are advised to abandon all oil facilities including the offshore rigs of Bonga and Agbami as we want to minimize casualties," MEND said.
MEND launched its most daring strike in June against Shell's $3.6 billion Bonga oilfield, which lies some 120 km (75 miles) from the coast, forcing the company to shut down the 220,000 bpd operation for several days.
MEND's other target, Chevron's Agbami oilfield, is Nigeria's newest oilfield. The facility, which started production in late July, is expected to pump around 100,000 bpd by February.
Shell and Chevron officials were not immediately available for comment.