Oil companies in Yemen's Hadramout and Shabwa provinces, including the main gas export facility at Belhaf, have suspended operations amid protests over the seizure of a presidential aide by Shi'ite fighters who control the capital Sanaa, local officials said on Monday. The Shi'ite Houthis seized President Abd-Rabbu Mansur Hadi's chief of staff, Ahmed Awad bin Mubarak, a native of the southern Shabwa province, on Saturday amid a dispute over a proposed new constitution that threatens to bring down the government. "Several oil firms with small production capacities have shutdown their operations in protest of the kidnapping," a local official in Shabwa told Reuters. Another official said all oil companies in Shabwa had suspended work as part of an understanding with the local tribesmen, who have been angered by bin Mubarak's seizure. Crude production from Yemen's Masila oilfields in Hadramout province also stopped due to protests over bin Mubarak's seizure, labour union officials told Reuters by telephone from the eastern Hadramout province. Yemen is a small producer with proven oil reserves of around 3 billion barrels, according to the U.S. Energy Information Administration (EIA). Yemen has two primary crude streams, the light and sweet Marib stream and the medium-gravity and more sulfur-rich Masila stream. According to the government, the southeast Masila Basin holds more than 80 percent of the country's total reserves, an EIA report said. The decision to shutdown production came following tribal leaders contacting the oil firms and giving them instructions, the officials said. Yemen's only gas terminal of Belhaf in Shabwa also stopped its operations after foreign experts were evacuated from the facility late on Sunday, the sources added. Total is the biggest investor in Yemen's gas export industry through its 40 percent shareholding in Yemen LNG; U.S.-based Hunt Oil has 17 percent, state-run Yemen Gas Co 17 percent and Korea Gas Corp (Kogas) 6 percent. On Monday, Houthi rebels led violent clashes in Sanaa in a district that houses the country's president and other high level security officials. Reuters