Authorities in Iraq have admitted that they have been forced to close the country's biggest oil refinery after tanker drivers stopped work because of death threats. The threats were in response to a steep rise in the price of petrol this month, which provoked widespread protests. The death threats were addressed to the plant's drivers. They began arriving on December 21. Four days later the refinery ceased production after hundreds of drivers stopped work over safety concerns.The stoppage will cause fuel shortages and electricity problems as far as Baghdad and across the north. Even before the latest incident, Iraqis had become accustomed to daily power cuts and having to wait hours to fill their petrol tanks. The Oil Ministry says it is developing a plan with the defence and interior ministries to protect routes of fuel distribution. The refinery plans to reopen within the next few days.