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 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.

“There are a lot of things that we don’t know, but that’s what we’ve seen so far,” Mr. Jassy said.

Amazon, along with its peers in Big Tech, has been on a frantic spree to develop data centers, massive remote buildings packed with servers that power cloud computing and artificial intelligence. In May, Mr. Jassy told investors that Amazon could have sold more cloud services if it had more data centers, which the company was building more rapidly.

On Thursday, Amazon reported that it spent more than $31 billion on capital expenses in the last quarter, about twice as much as a year earlier. Mr. Jassy said on the call that Amazon would spend about that much in each of the next two quarters as well, and that the backlog for the energy-hungry facilities could still drag on for several quarters.