By Liz Hampton

(Reuters) – Oil producer Diamondback Energy said the U.S. shale industry will struggle to continue to expand production at the current pace, with costs of new shale wells likely rising.

The aging of oil and gas wells, supply chain bottlenecks and investor focus on shareholder returns have led to slowing U.S. oil output gains, Diamondback Chief Executive Officer Travis Stice told investors on Tuesday during an earnings call.

(Reporting by Liz Hampton in Denver)