WASHINGTON (Reuters) -U.S. worker productivity grew faster than initially thought in the second quarter, curbing the rise in labor costs.

Nonfarm productivity, which measures hourly output per worker, increased at a 3.3% annualized rate last quarter, the Labor Department's Bureau of Labor Statistics said on Thursday.

That figure was revised up from the previously reported 2.4% pace of increase. Economists polled by Reuters had forecast productivity growth would be upgraded to a 2.7% rate.

Productivity decreased at a 1.8% rate in the first quarter. It grew at a 1.5% rate from a year ago, revised up from the 1.3% pace estimated last month. Productivity could get a boost from a boom in artificial intelligence investment.

Unit labor costs - the price of labor per single unit of output - increased at a 1.0% rate last quarter. They were revised down from the previously reported 1.6% growth pace. Labor costs increased at a 2.5% rate from a year ago, down from the previously reported 2.6% pace.