Tunis - Security forces on Monday fired tear gas at protesters as they tried to storm a gas and oil installation in southern Tunisia, local radio stations said.Residents have been camping outside the El Kamour gas and oil pumping station in the Tataouine region for around a month to demand they be given a share of local resources and priority in jobs in the sector.Tensions have been rising in recent days, with soldiers firing warning shots on Saturday to stop demonstrators entering the station's premises.It was the first such incident since President Beji Caid Essebsi said the army would protect key installations from being disrupted by protests over social and labour issues.Late on Sunday, the defence ministry in a statement warned the army would resort to force against anyone who tried to enter the grounds of these installations.The statement warns "all citizens of legal proceedings in the case of clashes with military or security units" and of possible casualties in "the case of a gradual escalation of use of force"."One must understand that attempting to enter by force an installation protected by the army... is not a peaceful act. It's an attempt to enter by force and it requires a reaction," ministry spokesman Belhassen Oueslati told Express FM radio on Monday.The ministry statement also said pumping at El Kamour had resumed "normally", after public radio on Saturday said protests had caused the installation to shut down."Following tensions... and to avoid any loss of human life, military units called on a specialised engineer to temporarily decrease pressure at the pumping station, then brought it back... to normal levels" on Sunday, the statement said.Prime Minister Youssef Chahed's unity government is facing an increasing wave of social unrest, especially in the North African country's interior. Protesters often stage sit-ins to block roads and access to key sites.