TOKYO — 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.

The decision, a product of months of deliberation, appeared calibrated to draw a line under what Mr. Abe and many Japanese see as an endless and enfeebling cycle of apologies for decades-old offenses. But Mr. Abe sought to do so while still addressing lingering resentment in China and South Korea, nations that bore the brunt of Japan’s often brutal empire building in the first half of the 20th century.