G20 governments endorse trade but tighten controls

Governments also have said they want to discuss climate change, efforts to reduce surplus production capacity in steel and other industries and limits on use of tax havens, though no detailed agreements are expected.

The summit is the first global event for British Prime Minister Theresa May after her country's June vote to leave the European Union, a move seen by some political analysts as the start of a possible wave of nations pulling back from economic integration.

Progress on initiatives such as Obama's Trans-Pacific Partnership and a WTO plan to help poor countries integrate into global markets has stalled.

[...] protectionist measures don't appear to be to blame for the latest trade slump, said Andrew Kenningham of Capital Economics, which is due mostly to the end of an era of rapid growth driven by China's integration into the global economy and manufacturing supply chains.

In May, the EU parliament passed a resolution calling for controls on Chinese imports in the event Beijing is declared a market economy, a status that makes it harder to pursue trade cases.

Envoys in Hangzhou plan to discuss how to reduce global production capacity for steel, according to Wally Adeyemo, Obama's deputy national security adviser for international economics.