WASHINGTON — The intelligence could come to President Trump secretly and urgently: The North Koreans have placed another intercontinental missile on its launching pad. In less than two hours, it could be fueled and ready for launch on a test flight into the Pacific Ocean or perhaps on a mission to strike American territory.

In that scenario, the American president could quickly set in motion a move long debated but never taken — a preventive military action inside North Korea aimed at disabling an imminent missile launch and sending an unmistakable “cease and desist” message to Kim Jong-un, the country’s volatile leader.

In a series of verbal warnings over the past several days, Mr. Trump has repeatedly raised the specter of military action toward North Korea. On Friday, he said on Twitter that “military solutions” were “locked and loaded,” retweeted a picture of a B-1 bomber based in Guam, and warned Mr. Kim.

“If he utters one threat, in the form of an overt threat, which by the way he has been uttering for years, and his family has been uttering for years, or if he does anything with respect to Guam, or any place else that’s an American territory or an American ally, he will truly regret it and he will regret it fast,” Mr. Trump told reporters.