BEIJING—China is prepared to take the helm of the global economy if Western nations abdicate their leadership role, a top Chinese diplomat said Monday, days after U.S. President Donald Trump pledged in his inaugural address to put “America first.”

“If it’s necessary for China to play the role of leader, then China must take on this responsibility,” Zhang Jun, head of the Chinese foreign ministry’s office of international economic affairs, told a small group of foreign reporters in Beijing.

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