Armed men in the Niger delta of Nigeria say they have attacked an oil pipeline overnight, putting a two-month truce with the government in doubt.
A faction of the Movement for the Emancipation of the Niger Delta said it attacked the pipeline.
A spokesman said it was because the government was delaying peace talks due to the absence of ill President Umaru Yar'Adua, who is in Saudi Arabia.
Attacks have cost Nigeria millions in lost revenue over the years.
The faction said, in an e-mailed statement, that the "warning strike" was carried out by 35 men on five boats with assault rifles, rocket launchers and heavy-calibre machine guns.
It said the pipeline was in Abonemma, about 50km (30 miles) west of Port Harcourt.
Nigeria's military has not commented on the attack.
Peace talks were suspended when President Yar'Adua was hospitalised in late November in Saudi Arabia.
Full story: BBC News at 10:53 GMT, Saturday, 19 December 2009 - Nigeria rebels attack oil pipeline
