WASHINGTON — President Trump told aides last year that he wanted US forces with bayonets to block people from crossing into the United States over the Mexico border, one of several proposals he floated at moments of peak frustration with his inability to contain a migration surge, according to current and former administration officials involved in those discussions.

Trump also suggested excavating a border trench, or moat, that could be stocked with dangerous reptiles, the officials said, adding that such ideas, along with the bayonets, were not taken especially seriously by White House aides.

The New York Times reported Tuesday on Trump’s proposal for a moat filled with snakes and alligators, along with his suggestion that US forces could open fire on migrants as they attempted to enter the country, potentially shooting at their legs to wound but not kill them.

The president denied those claims in a tweet Wednesday. ‘‘Now the press is trying to sell the fact that I wanted a Moat stuffed with alligators and snakes, with an electrified fence and sharp spikes on top, at our Southern Border,’’ he wrote. ‘‘I may be tough on Border Security, but not that tough. The press has gone Crazy. Fake News!’’

The Washington Post independently confirmed the president did say those things during border security meetings, including at moments when he demanded the wholesale closure of the Mexico border and appeared prepared to enforce the decree with violence.

Deputy White House press secretary Hogan Gidley declined to comment on the president’s suggestions, alleging that ‘‘there have been so many wild, inaccurate, and offensive fake news characterizations’’ surrounding his desires. Gidley said Trump has made clear that he wants to secure the border; Trump made immigration and border security central issues of his first presidential campaign and of White House tenure.

The idea for bayonets surfaced about the time Trump began sending soldiers to the border last year, said one of the officials in the discussions. The official, like others in this article, spoke on the condition of anonymity.

The defense secretary at the time, Jim Mattis, did not want soldiers to interact with migrants and did not want them to be armed. The deployment fell short of providing Trump with the kind of intimidating show of force he was seeking.

Staffers advised the president it would be illegal to use bayonets and warned that deploying such weapons would trigger a backlash. The officials said it was not clear whether Trump sought to have US soldiers wield the bayonets, or if border agents would carry them. The idea went nowhere.

‘‘Trump would be throwing extremes at the wall when he was frustrated,’’ said one former official, who, like others, characterized some of Trump’s suggestions as fanciful musings that aides did not interpret as serious directives.

The United States has a natural waterway, the Rio Grande, along nearly two-thirds of the US-Mexico border, and its lower section is a habitat for alligators and venomous snakes. The river, in places murky and with a deceptively strong current, has proven deadly to some migrants who have tried to wade, swim or boat across it to Texas.

Aides who participated in the meetings or who were later briefed said Homeland Security staffers and White House aides typically divided the president’s proposals into two categories. Those considered the most extreme were not acted upon, but others were taken more seriously or implemented, including Trump’s request to paint the border barrier black and top it with sharp spikes. Trump has boasted that the black paint absorbs heat from the desert sun and makes the barrier hot to touch.