US President Donald Trump’s threatened steel tariffs that don’t kick in for two weeks are impacting US buyers who already are seeing American-made metal cost more than imports.

New U.S. steel tariffs are set to disrupt a multi-billion dollar supply chain moving steel from China to the United States via third countries, ratcheting up competition in the global market and undercutting a vital source of sales for China's struggling steel sector.

Canada and Mexico are the leading exporters of steel to the US, but most of their products likely can be readily produced in the US, Bloomberg Intelligence analysis shows.

China's giant steel industry is facing mounting pressure on exports this year as it faces another wave of trade frictions from U.S. President Donald Trump's new tariffs. Trump announced plans earlier this month to impose 25% tariffs on all steel and aluminium imports into the United States,