Using the carefully chosen words that govern reckonings with Japan’s militarist past, Prime Minister Shinzo Abe reiterated his country’s official remorse for the catastrophe of World War II on Friday, the eve of the 70th anniversary of the war’s end.

In a nationally televised address, Mr. Abe described feelings of “profound grief” and offered “eternal, sincere condolences” for the dead. He said Japan had inflicted “immeasurable damage and suffering” when it “took the wrong course and advanced along the road to war.”

But in a potentially contentious break with previous expressions of contrition by Japanese leaders, he did not offer a new apology of his own.