US President Donald Trump on Friday launched a fierce attack on "predatory" trade practices, warning trading partners at the World Economic Forum here that Washington will not tolerate unfair practices.Speaking to the political and economic elite of the world, Trump said he would always put the US first when it came to trade, but "that does not mean America alone".Repeating his famous America-first message, the US President said: "The world is witnessing the resurgence of a strong and prosperous America."I believe in America. As President of the US, I will always put America First. Just like the leaders of other countries should put their countries first," he said, adding, that America first dosn't necessarily mean "America alone".Trump said that the US "will no longer turn a blind eye" to some economic practices he called "predatory behaviour"."We cannot have free and open trade if some countries exploit the system at the expense of others. We support free trade, but it needs to be fair and it needs to be reciprocal. In the end, unfair trade undermines us all."The US leader said in his address that "America is open for business and is competitive again"."The world is witnessing the resurgence of a strong and prosperous America … There has never been a better time to hire, to build, to invest and to grow in the United States. America is open for business," he said.He added: "Come to America, where you can innovate, create and build."