Nigerian militants released four foreign oil workers today to end a 19-day hostage crisis.
But they have threatened another wave of attacks on oil facilities in the world's eighth largest exporter.
The hostages - an American, Briton, Bulgarian and Honduran - were abducted from an offshore oilfield in the southern Niger Delta on January 11th during a six-week campaign of attacks on oil platforms and pipelines which cut output by a tenth.
The four men were flown from the delta by helicopter and taken to the capital Abuja, 300 miles to the north, to see President Olusegun Obasanjo.
Mr Obasanjo denounced the kidnappers, who had demanded more control over oil wealth, the release of two ethnic Ijaw leaders and compensation for pollution, as "rascals who are practising the things they watch on television".
The Ijaw are the biggest ethnic group in the delta.
A militant source said 100 million naira (€639,000) was paid for the hostages' release, but this was denied by the militants themselves.
The group reiterated a warning to foreigners to leave the delta, which pumps most of Nigeria's 2.4 million barrels a day, and said it aimed to cut oil exports by 30 per cent in February.