Japan Tobacco Inc.'s first-quarter operating profit declined 8.4 percent as domestic cigarette sales fell and the weakness of the Russian ruble hurt earnings from its biggest overseas market.

The company also agreed to buy Logic Technology Development LLC, a U.S. e-cigarette brand, as it expands in emerging products, Japan Tobacco said, without disclosing financial details.

Operating profit fell to ¥143.4 billion for the three months ended March from ¥156.6 billion for the same calendar period last year, Asia's largest listed cigarette maker said Thursday. Japan Tobacco provided a first-quarter "like-for-like" comparison as it is shifting to a new accounting period to match the calendar starting this year.