Nigerian militant group the Niger Delta Avengers said on Saturday it had carried out its first oil pipeline attack in the country's southern energy hub since declaring a break in hostilities in August to pursue talks with the government.
The Avengers have previously launched attacks that have reduced the OPEC member's crude oil production by around a third from the 2.1 million barrels per day average at the start of the year.
The group said in a statement on its website that it had "brought down oil production activities at the Bonny 48 inches crude oil export line" in an attack on Friday night.
An Avengers spokesman said in an emailed statement later that the attack took place in the sea near Bonny island in Rivers State, the location of a number of oil facilities. Reuters was not immediately able to independently verify the details.
The group, which wants a greater share of the OPEC member's wealth to go to the Niger Delta where most of the country's crude is produced, said the attack was a "wake up call" for the government and accused it of intimidating young people in the region since the ceasefire began.
"While we were promised that the concerns of the Niger Delta will be addressed once a truce is declared, the activities of the government and her agents are not assuring enough, there has been no progress," the group said.
But it added that it was still in favour of dialogue and negotiations. Earlier this month the Avengers told Reuters they had had no contact with the government since agreeing to halt hostilities.
An army offensive launched in late August against militant camps has raised tensions in the region amid claims, denied by the military, that troops have harassed locals.
Separately, the army said a soldier had been killed and two others were missing following an attack early on Saturday elsewhere in the region on troops by suspected militants from a different group.
Army spokesman Sani Usman said suspected militants linked to the Bakassi Strike Force attacked troops in Bakassi in Cross River State, about 100 miles (160 kilometres) away from the area in Rivers where the Avengers said they had carried out an attack.
"A soldier was killed in action, while two soldiers were missing in action," said Usman.