LAGOS, Nigeria (AP) _ The main militant group in Nigeria’s southern oil region declared a state of war Sunday after two days of clashes with government forces, launching reprisal raids and raising the specter of more conflict in Africa’s biggest oil producer. The group warned international oil companies to avoid the region or take “a foolhardy risk of attack.” The Movement for the Emancipation of the Niger Delta has mostly focused on hobbling Nigeria’s oil industry since it emerged nearly three years ago, bombing pipelines in hopes of forcing the federal government to send more money to the impoverished oil-producing south. But a military task force involving marine, land and air forces have stepped up their anti-militant activities in recent weeks. On Sunday, militants said they attacked soldiers protecting sites run by Chevron Corp. and Royal Dutch Shell âÄî payback for a rare ground battle Saturday when the armed forces attacked a militant base camp. “Following a previous warning that any attack on our positions will be tantamount to a declaration of an oil war, the Movement for the Emancipation of the Niger Delta has declared an oil war,” said a statement from the group, known by its acronym MEND. It was unclear whether the declaration would have any real effect in the Niger Delta. Neither side has sought a full-blown civil war, although Nigerian media have reported that some elements in the military are pushing for more robust attacks on the militants. The loose alliance of militant and criminal gangs steals Nigerian oil for sale overseas. Most fighting is focused on the oil industry, but a full-scale conflict with the military could leave the country’s oil-pumping infrastructure in tatters, while jeopardizing the militants’ own lucrative oil trade. While a wider civil war isn’t seen to be in either side’s interests, it is the doomsday scenario for the international oil companies, who would find it increasingly difficult to maintain the thousands of miles of pipelines connecting wells to export terminals. A shutdown of all oil production from Nigeria, one of the world’s top producers and an OPEC member, would cause further spikes in oil prices. The militants, who analysts say are motivated by money as well as politics, say they want more federally held oil funds for their states, which remain impoverished despite five decades of production. Their attacks have cut about one-fifth of Nigeria’s normal oil output, helping send crude prices to all-time highs in international markets. The militants said seven of their fighters died Saturday and claimed 22 troops were killed in the attack Sunday. Lt. Col. Sagir Musa, a spokesman for the military task force charged with calming the Niger Delta, acknowledged there was fighting Sunday near two sites operated by Chevron and Shell in Rivers State, but denied soldiers were killed. Representatives for Shell and Chevron said they were investigating reports of violence at their facilities. Private security contractors working in the oil industry, which often helps evacuate wounded military personnel, said at least three soldiers were injured and two civilians killed in the crossfire. The militants also said they blew up other pieces of oil infrastructure, but those claims could not be immediately verified. “All international oil and gas loading vessels entering the region are warned to drop anchor in the high sea or divert elsewhere until further notice. Failure to comply is taking a foolhardy risk of attack and destruction of the vessel,” the group said. The militants said they had attacked a military outpost in recent weeks, killing 29 troops in response to alleged killings of civilians. The government denied that any attacks took place. The accounts could not be independently verified. While the military often skirmishes with gunmen during chance boat encounters on the region’s waterways, it has avoided major attacks on militant camps and other permanent positions. The militants generally avoid the armed forces, sticking to the back creeks of the delta as they roam the region.