HANGZHOU, China — China agreed to cooperate more closely with its trading partners on its politically volatile steel exports as leaders of major economies ended a summit Monday with a forceful endorsement of free trade.

In a joint statement, Chinese President Xi Jinping, U.S. President Barack Obama and the leaders of Britain, Japan, Russia and other Group of 20 nations pledged to boost sluggish global growth by promoting innovation.

“The global recovery lacks momentum,” Xi told reporters after the meeting. “We need to do more to unlock the potential for medium and long-term growth.”

There was no mention of a global stimulus or other joint action, which officials said earlier was unworkable because economic conditions vary widely from country to country.

In an effort to shore up public support for trade, the leaders promised “inclusive growth” to spread the benefits to people who have been left behind by wrenching change. That reflects a recognition that economic strains are fueling tensions and a growing clamor to raise barriers against competition.

The statement expressed “opposition to protectionism.”