President Donald Trump said that Japan was declining to help open the Strait of Hormuz, a day after he made a joke about Pearl Harbor.

Following his Thursday meeting with Japanese Prime Minister Sanae Takaichi, Trump told Fox News host Martha MacCallum on Friday that the country would not assist with the fallout from the war in Iran because of "constitutional constraints."

"Japan is better ally than NATO," Trump reportedly said to MacCallum.

Japan's constitution bans the use of force except in defense of its territory. It's unclear whether the Japanese Self-Defense Force could be used to escort ships through the Middle Eastern waterway.

During his meeting with Takaichi, Trump compared his strikes on Iran to the bombing of Pearl Harbor.

"We didn't tell anybody about it because we wanted surprise. Who knows better about surprise than Japan? Why didn't you tell me about Pearl Harbor, OK?" the U.S. president joked.