(Reuters) - Traders boosted bets on Tuesday the Federal Reserve will start cutting its policy rate as soon as next month, as the White House said additional tariffs on imports from China will go into effect on Wednesday in a further escalation of trade hostilities that could slow the economy.

Traders put about a 56% chance of a Fed interest-rate cut in May, up from about 40% earlier in the day, based on the prices of short-term U.S. interest-rate futures traded at CME Group. They expect at least four more rate cuts through the end of the year.