Coca-Cola Co. reported rising drink volumes in its latest quarter, boosted by demand for diet sodas in the U.S. and experiments abroad. But it also said it would take the unusual step of raising prices on its carbonated sodas in the middle of the year.

Read: Coca-Cola earnings and revenue beat estimates

Chief Executive James Quincey said the price move was in response to rising costs, including higher freight rates and metal prices after the U.S. placed tariffs on Chinese imports earlier this year.

Read:Think tariffs are barely hurting earnings? Think again

“There is some broad-based push on input costs that have kind of come in and affected ours and many other industries as well,” Quincey said.

He said he expects the company’s bottlers and retailers to pass along the higher prices to consumers.

A Coke spokesman declined to provide details on the price increase.

The soda giant KO, +1.01% has been diversifying its portfolio away from sugary drinks, adding seltzer and soy beverages to its stable. Results for the June quarter, it said, were driven by Coca-Cola Zero Sugar, a diet version with a flavor closer to original Coke that has helped offset declining sales of traditional Coca-Cola.

An expanded version of this report appears on WSJ.com.

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