Nigeria's main militant group warned on Tuesday it may end a unilateral ceasefire and launch attacks across the Niger Delta.

The UK says it will not send soldiers to Nigeria to help tackle lawlessness in the restive Niger Delta, but will provide help in training.

The most high-profile rebel group in Nigeria's oil-rich Niger Delta said on Thursday it was suspending a two-week-old unilateral ceasefire.

With unrest in the Niger Delta cutting into oil output, Nigeria has made peace efforts a priority, but has little to show for its efforts.

Nigerian security forces have clashed with militants believed to be responsible for an attack on Royal Dutch Shell's main offshore Bonga oilfield.

Nigerian President Umaru Yar'Adua has ordered the country's armed forces to tighten security in the Niger Delta.

Nigeria has become the world piracy "hot spot", with its prized oil industry a particular target, and the raiders have exposed flaws in the country's security. Despite the massive revenues earned from oil, officials concede Nigeria is ill-equipped to combat pirates who ply the seas with speed boats, modern machine guns and radios.