US President Joe Biden has opposed the proposed sale of US Steel, a Pittsburgh-based steel manufacturer, to Japan's largest steel producer, Nippon Steel. Biden made the remarks to shore up support in the key swing state of Pennsylvania, where US Steel is headquartered and employs many workers. Biden and former President Donald Trump have said they do not support the $14.1 billion takeover deal, citing the need to protect American steel jobs. US Steelworkers union backs Biden's opposition, saying the company should remain under domestic ownership.