London (CNN Business) 1. Trade war escalates: The trade war between the United States and China is heating up just as President Donald Trump threatens new tariffs on goods from Mexico. For markets, that's a tough pill to swallow.

US stock futures point to a difficult start to the week after the Dow finished below 25,000 for the first time in four months on Friday. Dow futures were down 120 points on Monday, or 0.5%. The S&P 500 is poised to drop 0.4%, while the Nasdaq could shed 0.5%.

China increased tariffs on $60 billion worth of US goods last week in retaliation for the latest hike from the United States. In an official document released Sunday, Beijing blamed the United States for the breakdown in trade talks and said it will "not back down."

Meanwhile, the Trump administration is standing by the president's threat to impose a 5% tariff on all goods from Mexico starting June 10. Mexico's economy secretary is set to meet with US Secretary of Commerce Wilbur Ross Monday in Washington.

Trump has also taken aim at India. He announced Friday that he will remove the country from a special trade program on Wednesday.