Four workers were kidnapped on Saturday from an oil field in southern Libya, with two of them later released, Libya's National Oil Corporation said. The abductions at the Al-Sharara field will hit output in the country, whose fragile economy relies heavily on its oil supplies."Armed men kidnapped four engineers at dawn this morning - three Libyans and a Romanian," said Ramadan Saleh, in charge of security in Libya's southern Ubari region.Libya's National Oil Corporation confirmed in a statement that four workers were kidnapped by "unknown armed assailants", but said two have been released. The company said it was working with "appropriate authorities to resolve the issue", without giving further details of those abducted. "Oil wells in the surrounding area have been shut down as a precaution, and all other workers evacuated," the NOC said.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and FacebookThe Al-Sharara field is one of the biggest in oil-rich Libya.Saturday's closure is expected to slash production by 160,000 bpd, according to the NOC.The incident comes two days after the oil firm announced it would reopen another southern oil field, Al-Fil, which has been shut since February due to a strike over salaries.The NOC also said this week that exports would resume from terminals in eastern Libya's oil crescent, after shipments were stopped for more than two weeks due to a standoff between rival factions.Libya produced 1.6 million bpd of oil before dictator Muammar Gaddafi was toppled from power and killed in 2011. Production subsequently fell but recovered to reach one million bpd by the end of 2017, but recent turmoil has shown the industry remains vulnerable to the chaos engulfing the country.Two rival administrations continue to vie for power in Libya, while militias and jihadists have often targeted workers at energy facilities.