PITTSBURGH — United States Steel Corp. posted substantially lower third-quarter earnings as stronger sales failed to offset weakness in North America, plant shutdowns in Europe and acquisition-related costs.

The Pittsburgh-based company warned that the downward trend is likely to continue in the current quarter.

U.S. Steel on Tuesday reported earnings of $269 million, or $2.27 per share, for the three months ended Sept. 30, a 35-percent decline from $417 million, or $3.42 per share, a year earlier.

The results included a $27 million pretax charge for inventory acquired from Lone Star Technologies Inc., a Dallas-based welded pipe maker U.S. Steel bought earlier this year for $2 billion, and tax charges of $11 million.

Those charges reduced the profits of U.S. Steel, the largest U.S.-based steel maker, by $28 million, or 23 cents per share.

Analysts were looking for profits of $2.63 per share on $4.38 billion in revenue, according to Thomson Financial. Those estimates typically exclude one-time items.

But sales climbed 6 percent, to $4.35 billion from $4.11 billion during the same period last year.

U.S. Steel shares tumbled $7.88, or 7 percent, to close at $104.62 Tuesday. They gained 38 cents in after-hours trading.

John Surma, U.S. Steel's chairman and chief executive, said fourth-quarter results are expected to decline because of seasonal effects and several scheduled blast furnace outages.

On a conference call with analysts, Surma said steel market fundamentals generally were positive.

North American inventories and imports of flat-rolled steel — used in appliances and autos — are at relatively low levels, he said.

The weaker U.S. dollar, he said, should favor the company's customers over time.

U.S. Steel's European operation saw operating income shrink, partly because of plant shutdowns and higher raw material costs.

Results for its tubular business dropped mostly because of lower prices and the cost of integrating Lone Star into its operations. The Lone Star acquisition made U.S. Steel the largest maker of tubular steel in North America.

U.S. Steel also said it was starting a voluntary early retirement program at its operation in Slovakia.

During the quarter, U.S. Steel announced plans to pay about $1.1 billion for the Canadian steel maker Stelco Inc.

Stelco shareholders and regulators have approved the deal, which could be completed as early as today.