06/20/2008 -Royal Dutch Shell shut down production at its oil facility off the coast of Nigeria today after rebels attacked it Thursday, damaging equipment and taking an American hostage who was later released.

The Bonga oil field—discovered 75 miles off shore in 1995—accounts for 10 percent of the country's oil production. The field produced approximately 225,000 barrels of oil a day,reports The New York Times.

In response to the attack, President Umaru Yar'Adua ordered the Nigerian military to tighten security and hunt down the militants responsible for the attack, Reutersreports. The country's House of Representatives, meanwhile, called for an emergency meeting of government and private security and oil officials to discuss the attacks,according to Thompson Financial.

The Movement for the Emancipation of the Niger Delta (MEND) claimed responsibility for yesterday's attack in an e-mail sent to journalists. Known for attacking oil installations throughout the delta's network of creeks, the group claims Thursday's attack proved no oil installation in the region is safe.

“The location for today’s attack was deliberately chosen to remove any notion that offshore oil exploration is far from our reach,” said Jomo Gbomo, a spokesman for the group.

The group also threatened to expand its targets to include oil and gas tankers in Nigerian waters.

An umbrella group of decentralized tribal Ijaw militias, youth groups, and criminal gangs, MEND says it acts in retaliation for government corruption which allows Western oil companies to plunder the Niger Delta's resources while polluting their tribal lands without just compensation. The group wants a greater share of oil revenues reinvested locally.

Niger's government portrays MEND as a criminal organization that only enriches its membership with ransoms paid out by oil companies.

As Security Management reported last September, the Niger Delta region's share of oil revenues has plummetted in the last half century:

During the early 1960s, oil revenue distributed back to the oil producing states hovered around 50 percent, but nosedived to 1.5 percent in 1984, and hopped to 13 percent under the 1999 constitution, said Frederic Ngoga-Gateretse, Africa regional manager for iJet, an intelligence and security consultancy.

While the region provides 75 percent of the government’s revenue from minerals, it lacks critical infrastructure and social goods such as clean water and good schools.

MEND attacks have caused a 20 percent reduction in oil output, which has helped drive oil prices up internationally, the BBCreports. The group's activities have also allowed Angola to overtake Nigeria as the continent's biggest oil producer.