International Monetary Fund chief Christine Lagarde has cautioned the United States against putting up barriers to trade.

In an interview with Argentine daily La Nacion, she said trade wars leave no winners.

The IMF chief said poor countries and poor people in rich countries have benefited from the surge in global trade over the past decade but some regions and industries have suffered.

She said the global economy is in good shape, with 3.9 percent growth projected this year.