In an apparent awkward moment at the Oval Office on Thursday stateside, U.S. President Donald Trump referenced Pearl Harbor in his first meeting with Japan's Prime Minister Sanae Takaichi after her landslide electoral victory.

When asked by a Japanese reporter on why the U.S. did not inform allies such as Japan before carrying out the attacks against Iran on Feb. 28, the U.S. president said it was to maintain the element of surprise.

"Who knows better about that. Why didn't you tell me about Pearl Harbor? You believe in surprise much more so than I."

Trump was referencing the surprise Japanese attack on the U.S. Pacific Fleet in 1941, which saw the deaths of over 2,400 personnel and drew the U.S. into World War II.

Takaichi appeared to draw a deep breath and lean back in her seat with an uneasy expression.

Trump said that the surprise attack on Iran had helped the U.S., adding that it "knocked out 50% of what we anticipated" in the country within the first two days.

During the meeting, Trump praised Japan for "stepping up" to assist in efforts to secure the Strait of Hormuz, "unlike NATO."

Before the meeting, Japan, as well as Britain, France, Germany, Italy and the Netherlands had released a joint statement expressing their readiness to "contribute to appropriate efforts to ensure safe passage through the Strait."

Trump had called on Japan and other countries to help secure the Strait of Hormuz, but Takaichi had reportedly said Monday that there were no plans to dispatch naval vessels to escort boats in the Middle East.

Her office also said in a post on X that there was "no specific request from the United States to Japan for the dispatch of vessels."

Japan's prime minister on Tuesday said that the government was considering what could be done within the framework of the country's law. Japan's Self-Defense Forces are governed by its pacifist constitution, that renounces war and the threat or use of force for settling international disputes.

Trump had taken aim at NATO allies earlier this week, saying that the alliance was "making a very foolish mistake" by not getting involved in the war.

In response, German Defense Minister Boris Pistorius reportedly said on Monday that "This is not our war, we have not started it," a stance that was also adopted by French President Emmanuel Macron.

Subsequently, Germany's Chancellor Friedrich Merz said on Thursday that "we have declared that as long as the war continues, we will not participate in ensuring freedom of navigation in the Strait ​of Hormuz, for example, by military means," according to Reuters.