Ecuador President Rafael Correa said major oil exploration in an unspoilt Amazon nature reserve could go ahead after the failure of an ambitious plan to secure billions of dollars in donations to avoid drilling in the area. In an address to the nation, Correa said Thursday he would seek authorization from lawmakers to allow drilling in a region of the Yasuni National Park, which was designated a world biosphere reserve by UNESCO in 1989. \"With deep sadness but also with absolute responsibility to our people and history, I have had to take one of the hardest decisions of my government,\" said Correa as he reversed an initiative he had first mooted in 2007. Three wells in the Yasuni reserve, which is home to several nomadic Indian tribes, are believed to hold around 920 million barrels of oil. Correa had sought to leave the oil untouched in order to avoid an estimated 400 million tons of carbon dioxide emissions being pumped into the Earth\'s atmosphere -- provided the international community would stump up $3.6 billion. However in the six years since the initiative was launched, Ecuador has received just $13.3 million -- equivalent to 0.37 percent of the hoped-for total, Correa said. \"The world has failed us so I have requested that in the national interest the National Assembly allows us to develop Yasuni,\" Correa said. Ecuador\'s 2008 constitution prevents the exploitation of non-renewable resources in protected areas, but allows the president to request a waiving of the rule if the \"national interest\" dictates it. Correa said any development would leave 99 percent of Yasuni untouched. \"The mining activity cannot develop in an area exceeding one percent of the Yasuni National Park,\" he said. \"This decision is disappointing to all of us but it is necessary. Not to do it would be to the detriment of our people. History will judge us,\" he said. Donations to the fund made by private companies or countries including Belgium, Chile, France, Italy, Spain and Indonesia had been placed in a trust administered by the United Nations Development Program and would be returned.