Officials in Shanghai promised Friday to ease anti-virus controls on truck drivers that are hampering food supplies and trade as they try to revive the local economy while millions of people are still confined to their homes.

A deputy mayor, Zhang Wei, promised “every effort” to resolve problems that prompted complaints about lack of access to food and fears that the shutdown, which confined most of Shanghai’s 25 million people to their homes, might disrupt global trade.

On Friday, the government reported 11 coronavirus deaths and 17,529 new cases in Shanghai. All but 1,931 of the new cases had no symptoms. Shanghai’s cases accounted for 95% of the 18,598 new cases on China’s mainland, of which 2,133 had symptoms.

Shanghai leaders are scrambling to ease the impact of a “zero-COVID” strategy that shut down most businesses starting March 28.

Authorities have tried to increase food deliveries and the flow of goods to the Shanghai port, the world’s busiest, by creating electronic passes for truck drivers to cross city and province boundaries, Zhang said at a news conference, according to state media.