BEIJING, China -- China will continue to open to the world, President Xi Jinping told a trade summit on Wednesday, just days after Beijing doubled down on its strict border controls.

Xi's remarks come as many foreign businesses have found their operations halted due to a lingering Covid-19 lockdown in financial hub Shanghai, with the American Chamber of Commerce warning it was bracing for an "exodus" of foreign talent due to unrelenting restrictions.

Beijing has been digging its heels in on a strict zero-Covid policy of stamping out clusters as they emerge, but an Omicron flare-up has resulted in tangled supply chains as cities rolled out movement curbs.

On Wednesday, China's top leader Xi "stressed that China's resolve to open up at a high standard will not change," according to a foreign ministry readout of his speech.

"The door of China will open still wider to the world," he added in the video address.

He also said that China would "continue to foster an enabling business environment" that is up to international standards.

But just days ago, immigration authorities reiterated rules to limit outbound travel by its citizens and China's business groups have flagged operating challenges due to lockdowns and other Covid-19 policies.

The German Chamber of Commerce found in a survey this month that only a small number of firms could resume production, while foreign staff are increasingly planning to leave over China's pandemic strategy.

There has also been a plunge in confidence, with the European Union Chamber of Commerce saying that containment measures across cities had caused massive disruptions.

But Xi struck a hopeful note on Wednesday, calling for a "balance" between pandemic response and economic development, as well as stronger macroeconomic policy coordination across countries.

Most foreigners have been banned from entering China since the spring of 2020 over coronavirus restrictions.