Alleged Port Authority bomber Akayed Ullah wanted to send a message straight to the White House: ‘Trump you failed to protect your nation.”

That’s what the 27-year-old ISIS adherent wrote on his Facebook page while on his way to blow himself up at the bustling transit hub Monday morning, according to a federal complaint filed Tuesday.

He had also written notes in his passport, including one “particularly chilling note”: “O AMERICA, DIE IN YOUR RAGE,” Acting US Attorney Joon Kim said at a press conference Tuesday.

The charges also reveal that the Bangladesh-born cabbie’s online radicalization began in 2014, and he began researching how to build bombs a year ago — although he only started working on his plan to attack the city a few weeks ago, and constructed his crude explosive device at his Brooklyn home a week ago.

“His admissions included a statement that he did this in support of ISIS, that he had been radicalized in view of propaganda from ISIS,” Kim told reporters.

“He also made statements … about issues he had with America’s Middle East policies.”

Ullah built the bomb for “maximum damage,” federal prosecutors charge — filling it with metal screws — and choosing to detonate it on a workday because “he believed that there would be more people.”

“Ullah had hoped to die in his own misguided rage, taking as many innocent people as he could with him,” Kim said.

“But through incredibly good fortune his bomb did not seriously injure anyone other than himself.”

The prosecutor and other law enforcement officials refused to comment on reports that Ullah had chosen the specific location for his attack in part because of Christmas posters there — or whether he was on any watchlists.

Ullah is expected to appear before a judge either later Tuesday or on Wednesday, likely via video from his hospital bed.