Chinese President Xi Jinping repeated pledges to boost exports and improve market access for foreign firms as he opened an import-export fair in Shanghai on Monday.

Xi, who has positioned himself as a defender of free trade in contrast with US President Donald Trump’s more protectionist policies, called on other countries to "pursue an open policy, explicitly oppose protectionism and unilateralism and strive to enhance the level of opening up."

"Openness brings progress, while seclusion leads to backwardness," Xi said in his keynote speech at the China International Import Expo in Shanghai, which was joined by about 3,000 companies from around the world.

China, battered by a protracted tariff war with the United States, is trying to boost trade with other parts of the world. Beijing, however, faces criticism about maintaining high tariffs and strict market barriers while benefitting from other countries’ market openness.

Many of the developed economies refused to send high-level officials to attend the fair. Out of the G20 powers, only Russia sent a head of state or government, Prime Minister Dmitry Medvedev.

Addressing concerns that the US trade war has contributed to slowing down the economy, Xi said China’s economy is "truly performing well within the reasonable range."

Xi and Trump are set to meet at the G20 summit in Argentina later this month. The two leaders discussed trade in a phone call Thursday, which Beijing later described as having been "extremely positive."