Libya will resume pumping crude “soon” at Sharara, its biggest oil field, after an attack that halted output, reducing the North African nation’s production by almost a third, an official said.

Sharara was shut as a precaution after gunmen stormed the on-site production compound, Mansur Abdallah, director of oil movement at the Zawiya refinery and oil port, said in a telephone interview. “The armed group left after stealing the cars, and production should resume soon,” he said.

The oil field is 720 km (450 miles) south of Zawiya, and the two sites are connected by a pipeline. While it has a similar capacity to the Waha field in central Libya, Sharara is the nation’s largest producer, with an output of 290,000 bbl/d before the latest shutdown, Abdallah said.

Libya, which is trying to restore output after more than a year of political unrest and violence, produced 850,000 bbl/d last month, according to Bloomberg estimates. The country pumped 1.6 MMbbl/d before the 2011 ouster of former leader Muammar Qaddafi.

Output has recovered after dropping to as little as 215,000 bbl/d in April. Warring factions pledged to keep oil flowing, and the state-run National Oil Corp. refrained from taking sides amid political disputes. The country is split between an Islamist-led administration that took control of Tripoli, the capital, a few months ago, and an internationally- recognized government in eastern Libya.

Brent crude rebounded from $82.35 a barrel to a high of $83.27 in about one hour of trading from 8:30 a.m. London time, after news that the Sharara field would soon resume output. The benchmark grade was trading at $82.23 a barrel on the London- based ICE Futures Europe exchange at 1:42 p.m.