Donald Trump floated adding a moat filled with snakes and alligators at the border and shooting border jumpers in the legs as a solution to the influx of illegal immigration coming from the south, it was revealed Tuesday.

During a private March meeting with White House advisers, the president asked for cost estimates on several ideas he had that he felt would stop migrants from illegally crossing into the U.S., more than a dozen White House and administration officials directly involved in the events revealed in a new book.

The book, 'Border Wars: Inside Trump's Assault on Immigration' by New York Times Washington correspondent Michael D. Shear and Julie Hirschfeld Davis, will be published by Simon & Schuster on October 8, but excerpts were adapted and published on the Times' website Tuesday.

One idea he proposed was shutting down the entire 2,000-mile border the U.S. shares with Mexico by noon the following day.

Donald Trump was revealed to have made even more unattainable proposals at the border in March meetings, including closing the entire 2,000-mile border by noon the next day

One idea, sources reveal, included a snake or alligator-filled moat at the border wall

Another included shooting migrants making a dash for the border in the legs to slow them down

Some of his other more outlandish proposals included a snake or alligator-filled trench at the southern border or electrifying the border wall and adding spikes at the tip that could pierce human flesh so people couldn't climb over it.

Publicly, Trump talked about border patrol agents throwing rocks at migrants, but backed off when staff informed him that it was illegal. But aides recalled that he later brought up the idea of shooting migrants in the legs to slow them down as they made a dash for the U.S. The aides had to inform him that was also against the law.

'The president was frustrated and I think he took that moment to hit the reset button,' Thomas Homan, who had served as Mr. Trump's acting director of Immigration and Customs Enforcement, recalled. 'The president wanted it to be fixed quickly.'

Back in May, reports emerged that Trump was micromanaging the border wall construction down to the smallest details, including wanting it to be painted a 'flat black' so it would absorb more heat in the summer and make it harder for climbers to scale the metal.

Reports from that time also revealed that the president considered a design plan that included a field-tested anti-climbing surface and rounded metal cylinders, but he said he didn't like the appearance, claiming metal points would look more intimidating.

He told a group of aides that spikes would cut climbers' hands and be a more effective in deterring them from scaling the wall.

Not only did Trump make the suggestions so it would be hard for border jumpers to cross, but also so it would be visually appealing and threatening.

At the time of his inquiry about his preferences for the border wall, then-Secretary of Homeland Security Kirstjen Nielsen found herself being the ones who had to constantly tell the president he couldn't have what he wanted.

When Trump said he wanted 'flat black' paint, Nielsen informed him it would cost an extra $1 million per mile, and when he wanted wall construction to be sped up, she told him he would need to obtain permission from landowners.

Then-National Security Secretary Kirstjen Nielsen was often the one who had to tell Trump his ideas couldn't happen. He responded by cutting her off during a a briefing on the legal authority to take down drones. 'Kirstjen, you didn't hear me the first time, honey,' Trump said, according to the sources. 'Shoot 'em down. Sweetheart, just shoot 'em out of the sky, OK?' he said, cutting her off midsentence

He told Nielsen they should just take the land and let the property owners sue them.

Two people familiar with a particular conversation said when Nielsen tried to turn the conversation away from incessant ranting about the border wall, the president condescendingly called her 'honey' and 'sweetheart.'

During a briefing on the legal authority to take down drones, Trump cut her off in the middle of her sentence.

'Kirstjen, you didn't hear me the first time, honey,' Trump said, according to the sources. 'Shoot 'em down. Sweetheart, just shoot 'em out of the sky, OK?'

Nielsen was ousted as homeland secretary in early April after a tumultuous tenure in charge of the border security agency, a post that often made her the target of Trump's criticism.

'I have determined that it is the right time for me to step aside,' she said in her resignation letter. 'I hope that the next secretary will have the support of Congress and the courts in fixing the laws which have impeded our ability to fully secure America's borders and which have contributed to discord in our nation's discourse.'