Chile, the world's biggest copper producer, says it is awaiting an "official" follow-up on US President Donald Trump's announcement of a 50 percent tariff on imports of the metal. The South American country is responsible for nearly a quarter of global copper supply, which contributes 10 to 15 percent to its GDP. "There has been no official notification, and consequently, we also do not know the precise scope of these decisions, which have been communicated in still very general terms," says Chilean Foreign Affairs Minister Alberto van Klaveren at a press conference in Santiago. IMAGES AND SOUNDBITES