The oil pipelines are a frequent target of extortion and bombing campaigns by the National Liberation Army (ELN) and, more recently, the Revolutionary Armed Forces of Colombia (FARC). The bombings, which have occurred on average once every 5 days, have caused substantial environmental damage, often in fragile rainforests and jungles, as well as causing significant loss of life. In April 1999 in Cartagena de Indias, Clinton's Secretary of Energy Bill Richardson spoke before investors from the United States, Canada and other countries. He expressed his government's willingness to use military aid to support the investment that they and their allies were going to make in Colombia, especially in strategically important sectors like mining and energy.