The U.S.-China trade deficit has gotten even wider. President Donald Trump says that’s the wrong direction, which is why he’s dispatched a posse of high-level officials to Beijing in hopes of hammering out a better deal.

The merchandise trade gap with China widened by 16 percent to $91.1 billion in the first three months of the year, according to Commerce Department figures released Thursday. China is America’s biggest trading partner so far this year, compared with the first quarter of 2017, when Canada held the top spot.

The news on the export-import gap comes amid rising concern that the world’s two-largest economies are heading to a prolonged, painful trade spat. Top officials from the Trump administration started discussions in Beijing on Thursday. China says it’s not willing to back down on key issues or submit to any U.S. threats.