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May 6 (Reuters) - Italian steel pipe maker Tenaris TENR.MI warned late on Wednesday that it expects second-quarter sales to be impacted by lower shipments in the Middle East due to the conflict in the region.

The U.S.-Israel war on Iran has led to a blockade of the Strait of Hormuz, which before the war handled one-fifth of the world's oil and gas supply, sending energy prices soaring.

Tenaris, which makes pipes for the energy industry, said its margins would be impacted in the second quarter due to higher logistics costs.

The Luxembourg-based company expects sales and margins to recover in the second half of the year if the key waterway in the Middle East is reopened.

Separately, the company also said it has appointed Gabriel Podskubka as CEO, replacing Paolo Rocca, who will serve as chairman of the board.

The exploration pipeline maker's first-quarter sales rose 6% to $3.1 billion, as strong sales growth of 19% in North America helped offset a weak performance in Asia Pacific, the Middle East and Africa, where revenue declined 6%.

Earnings before interest, taxes, depreciation, and amortization (EBITDA) rose 14% to $735 million.

Tenaris' margins remained stable, with EBITDA margin for the quarter steady at 23.7%. Net income increased 9% to $564 million.