The impact of China's economic slowdown on the global economy is bigger than previously thought, the head of the International Monetary Fund said Tuesday.

The slowdown of Chinese growth has "probably more spillover effects in the region in particular than what was anticipated," Christine Lagarde said in a speech at the Brookings Institution, a Washington think tank.

According to Lagarde, the Chinese cooling has "downside risks... greater than they were estimated."

"Growth is lower," she said, referring to the global economy.

China's slowdown, and questions about the government's ability to manage it, have spurred concerns about the health of the world's second-largest economy that have rattled financial markets in recent months.

Lagarde noted the easing Chinese growth had already helped push commodity prices lower, putting pressure on export-led economies and their public finances.

Her remarks came as Chinese President Xi Jinping began his first state visit to the United States in the West Coast technology and aviation hub of Seattle Tuesday, aiming to woo US businesses. President Barack Obama will host Xi for talks at the White House on Friday.