(Bloomberg) — Oil shipments were halted from at least three ports in Libya, according to people familiar with the matter, as the National Oil Corp. warned that planned stoppages could cut more than half of the nation’s crude output.Exports have been frozen at Ras Lanuf, Sidra and Brega, the people said, a day before members of the North African’s country’s warring factions are due to attend a summit in Berlin to try to resolve the conflict. Earlier Saturday, a NOC official said all oil shipments from ports in central and eastern Libya, except Zueitina, were due to halt after direct instructions from the Libyan National Army, the force based in the country’s east.The LNA is controlled by Khalifa Haftar, whose forces have been trying to overthrow the United Nations-backed government in Tripoli and have besieged the capital city.A NOC official said that a broader stoppage would result in at least 700,000 barrels per day of Libya’s oil output going offline. On Thursday, it announced daily production of 1.17 million barrels.The LNA‘s spokesman, Ahmed al-Mismari, said in statement overnight that his forces were responding to the will of the people, after eastern tribes staged protests demanding an oil-production freeze.To contact the reporter on this story: Salma El Wardany in Cairo at selwardany@bloomberg.netTo contact the editors responsible for this story: Andrew Davis at adavis@jefferies.comMichael Gunn, Andrew DavisFor more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.