WASHINGTON — The State Department is giving immigration and consular officials new grounds to deny entry to visitors to the United States or to kick them out if they are already here.

In a cable to American embassies around the world, Secretary of State Rex W. Tillerson wrote that visitors who require a visa before entering the United States must then follow through on their stated plans for at least three months. If in that period they do something they failed to mention in an interview with a consular official — such as marry an American citizen, go to school or get a job — it will be presumed that they have deliberately lied.

That would make it difficult, if not impossible, for them to renew a visa, get a new one or change their status. And if they were still in the United States, it would make those visitors eligible for deportation.

Changes of plans that occur after three months may still be problematic but are not presumed to be the result of “willful misrepresentation,” the cable said. Under previous rules, a change in plans was deemed to be misrepresentation only for the first month after arrival in the United States.