YENAGOA, Nigeria (Reuters) - Militants launched a fresh round of attacks on oil pipelines in Nigeria’s southern Niger Delta energy hub belonging to Italy’s Eni and Aiteo, Nigerian security forces, Eni and a militant group said.

The attacks are the latest in a spate targeting oil and gas facilities in the OPEC member’s Niger Delta region over the last few months which briefly pushed oil production this spring to 30-year lows.

The renewed violence could further cut into exports that were depressed as a result of infrastructure damage, underscoring the serious security threat to the oil production on which Nigeria relies for around 70 percent of its revenue.

Niger Delta Avengers, the group that has carried out most of the attacks, said on its website that it blew up the Nembe 1, 2 and 3 trunkline in Bayelsa and Rivers states which is owned by the Aiteo group in an early hours attack.(bit.ly/29DiMc4)

A spokesman for Eni confirmed that a separate attack on a crude pipeline in Bayelsa state, operated through its subsidiary, Nigerian Agip Oil Company, had taken place. No group has claimed responsibility for that attack.

The company said the impact on the group’s equity production was 4,000 barrels of oil equivalent per day.

The Nembe Creek Trunk Line (NCTL), a 100-kilometre long pipeline capable of carrying 600,000 barrels per day (bpd), moves Bonny Light crude oil to the export terminal.

Shell sold the line to Aiteo last year, but relies on it to get Bonny Light to international buyers.

On Thursday, Shell lifted force majeure - a legal clause that allows it to stop deliveries without breaching contracts - on Bonny Light that had been in place since early May following the closure of the NCTL for repairs. A total of 240,000 bpd of exports had been planned for July.

Eni’s Brass River crude remained under force majeure declared after previous attacks, but it has been exporting crude oil even as the force majeure was in place.

The Avengers have claimed responsibility for at least five attacks since Sunday, after around two weeks in which none occurred. Petroleum Ministry sources said in late June that a month-long truce was agreed with militants but the Avengers said they did not “remember” such an agreement.

Oil Minister Emmanuel Ibe Kachikwu, speaking at a state oil company event on Friday, said production - which was 2.2 million bpd at the start of the year - stood at 1.9 million bpd.

He also said repair work on the pipeline feeding Forcados crude oil to the export terminal was expected to be completed at the end of July.

The pipeline -- operated by SPDC, a local affiliate of Shell -- has been under force majeure since Feb. 21, a week after a leak forced a halt to loadings to the export platform. The Avengers said they attacked the pipeline, causing the leak.