South Korean technology giant Samsung Electronics warned on Wednesday U.S. tariffs could cut demand for products such as smartphones, making it difficult to predict future performance. Samsung said it expected its semiconductor business to encounter greater uncertainties throughout the year, while its smartphone shipments faced downward pressure in the second quarter. The cautious outlook from one of the world's biggest electronics manufacturers reflects the uncertainties roiling global trade due to U.S. President Donald Trump's tariff war, and comes a day after General Motors pulled its annual forecast.