Nigerian President Olusegun Obasanjo says his government will no longer tolerate kidnappings in the oil-rich south and ordered the military to respond with force.
Mr. Obasanjo said in a statement late Tuesday that security forces will begin round-the-clock patrols of the Niger Delta region. He also threatened to sanction companies if they pay ransom to kidnappers.
Kidnappings have become common in the oil-rich Niger Delta, where militants are demanding that local communities receive a larger share of oil revenues.
At least 14 oil workers have been kidnaped in the last 10 days. Of those, nine have been released, all unharmed. The whereabouts of two Germans, two Britons and an Irish man are still unknown.
In all the cases, it remains unclear who seized the workers or whether ransom money was demanded for their release.
Tuesday, kidnappers released two Norwegian and two Ukrainian oil workers. On Monday, five hostages were released - a Belgian, a Moroccan and three Philippine nationals.
At the start of the year, Nigeria was producing 2.5 million barrels of oil per day. But the repeat kidnappings and attacks on oil facilities have cut the country's oil production by at least 20 percent since February.
Some information for this report was provided by AP and Reuters.