BENGHAZI, Libya (Reuters) - East Libyan military forces control a pumping substation for the El Sharara oilfield but the main production area is still occupied by armed tribesmen, a field engineer said on Thursday.

FILE PHOTO: A general view of the El Sharara oilfield, Libya December 3, 2014. REUTERS/Ismail Zitouny/File Photo

The Libyan National Army (LNA), based in the east of the politically divided country, said on Wednesday it had seized the 315,000 barrels per day field from tribesmen and protesters who forced operations to halt when they took the site on Dec. 8.

The engineer, who asked not to be identified, said a convoy of LNA vehicles had arrived at a substation about 20 km (12 miles) from main field, which extends for 40 km (25 miles) in Libya’s southern desert.

He said the field perimeter was not fenced off and said the LNA was still trying to negotiate access to the main facility with the tribesman and protesters, who had taken the field demanding salary payments and development funds.

The National Oil Corporation, the state-owned oil firm based in the west of Libya, shut production as a result of the protest and declared force majeure, a waiver on its contracts.

The LNA, loyal to Khalifa Haftar, a commander whose powerbase is the eastern city of Benghazi, had demanded on Wednesday that production resume and force majeure be lifted.

NOC and the internationally recognized government, also based in the Tripoli in Libya’s west, declined to comment.

Oil output from the OPEC state has been disrupted since conflict erupted in 2011 and a political wedge was driven down the middle of the country. Protesters and armed groups have often targeted oilfields and energy infrastructure.

Haftar’s LNA seized Benghazi, Libya’s second-largest city, in 2017, expelling Islamist and other fighters there. The LNA said last month it was launching an offensive to fight militants and secure oilfields in the south.

A resident in Ubari, a town close to El Sharara, said one LNA unit had attacked by an unknown group in the area.