Despite uncertainty over President Trump’s trade war, Amazon on Thursday reported surprising resilience among the consumers who drive its retail business. But profit margins tightened at its cloud computing service, and executives cautioned there could be turbulence ahead.

Overall, sales from April through June at the e-commerce giant rose to $$167.7 billion, 13 percent more than in the same period a year earlier. Profit was $18.2 billion, up 35 percent.

For the current quarter, which ends in September, Amazon told investors to expect sales of $174 billion to $179.5 billion, and operating profits between $15.5 and $20.5 billion. The guidance showed confidence that customers will keep spending, but reflected a broad range of how much it will cost to serve them.

Customers have kept buying, and prices have not broadly increased because of tariffs, Andy Jassy, Amazon’s chief executive, said on a call with investors. That could change later this year, he cautioned, as Amazon and the other sellers on its marketplace burn through the inventory they have stocked in the United States.