A pipeline explosion in southern Bolivia that will force a 10 percent cut in natural gas exports to Brazil was caused by anti-government protestors, the head of the state energy company said on Wednesday. Santos Ramirez called the explosion “a terrorist attack.” Company officials said protesters closed a valve, creating pressure that burst the pipeline and caused a fire near the border with Paraguay. Ramirez said the pipeline blast reduced by 3 million the 30 million cubic meters of gas Bolivia sends Brazil each day.