The Niger Delta Avengers, a militant group which has been carrying out attacks on Nigerian oil facilities in the last few months, claimed responsibility on Sunday for five new attacks in the southern energy hub since Friday.

Until today, the group had not laid claim to any attacks in the Niger Delta — the source of most of the OPEC member’s oil — since June 16.

Petroleum ministry sources said in late June that a month-long truce had been agreed with militants. But the Avengers said they did not “remember” agreeing to a ceasefire.

Attacks in the Niger Delta have pushed Nigerian crude production to 30-year lows, although the Nigerian National Petroleum Corporation (NNPC) said last week that output was rising due to repairs and a fall-off in attacks.

In messages posted on Twitter in the early hours of Sunday, the Avengers said they had attacked a pipeline connected to the Warri refinery operated by NNPC on Friday night.

They added that on Saturday night they blew up two lines close to Batan flow station in Delta state run by NPDC, a subsidiary of NNPC.

The militants also said two Chevron facilities close to Abiteye flow station, in Delta state, came under attack in the early hours of Sunday.

Residents in some of these areas reported hearing blasts.

“All five operations” were carried out by Avengers “strike team”, the group said.

An NNPC spokesman could not be contacted to comment on the group’s statements.

“As a matter of long-standing policy, we do not comment on the safety and security of our personnel and operations,” said Chevron spokeswoman Isabel Ordonez.

The militants say they want a greater share of Nigeria’s oil wealth — which accounts for around 70 percent of national income — to be passed on to communities in the impoverished region and for areas blighted by oil spills to be cleaned.

On Thursday, President Muhammadu Buhari hosted a group of community leaders from the Delta and urged them to pacify people in the restive region where anger is widespread.

Eric Omare, of the Ijaw Youth Council (IYC) which represents the Delta’s biggest ethnic group, said the “resumption” of attacks was “worrisome”, adding that the government had failed to build on goodwill generated by the oil minister’s visit to the region in June.

“The federal government has not taken any practical step towards resolving the issues,” he said.

(Additional reporting by Anamesere Igboeroteonwu; Editing by Dan Grebler, Stephen Coates and Richard Balmforth)