(ABC News) - The man accused of detonating an explosive in the New York City subway system wrote on Facebook the morning of his alleged attack, “Trump you failed to protect your nation," according to the federal complaint against him.

Akayed Ullah, 27, an immigrant from Bangladesh, is accused of setting off the homemade bomb in an underground passageway near the Port Authority Bus Terminal Monday morning, sending commuters scrambling to evacuate the major transit hub just blocks from Times Square.

He allegedly selected the location and time to maximize human casualties, according to officials.

Joon Kim, acting U.S. attorney for the Southern District of New York, said at a news conference today that Ullah allegedly aimed to "murder as many innocent human beings as he could and to blow himself up in the process -- all in support of a vicious terrorist cause."

Despite the rush-hour crowds, however, only five people suffered minor injuries, officials said. Ullah was badly injured.

Ullah made statements to police indicating he “was inspired by ISIS to carry out” the attack and said, “I did it for the Islamic State,” according to the charging document.

Ullah's radicalization began in at least 2014 when he began viewing pro-ISIS material online, the document stated.

Some of the material he viewed included instructions to attack in homelands if unable to travel overseas to join ISIS on the battlefield, the document alleged.

Inside Ullah's passport was a handwritten notation: "O America die in your rage," the document said.

There is no evidence he received funding or specific direction from any overseas group, according to police sources.

Ullah is charged with five federal counts, including the use of a weapon of mass destruction and bombing a place of public use. Ullah could face life in prison. The death penalty is not a possibility in this case because there were no deaths resulting from his alleged crimes.

Ullah began researching how to build improvised explosive devices a year ago, the charging document said.

Ullah built the bomb in his Brooklyn home a week before his alleged attack and began compiling materials a few weeks earlier, according to the complaint.

"He had strapped to his body an IED [improvised explosive device], a pipe bomb that he had made using a metal pipe filled with … screws held together under his jacket with wires and zip ties," Kim said.

The charging document said law enforcement personnel found a 9-volt battery inside Ullah’s pants pocket, wires connected to the battery running under his jacket and fragments of metal pipe. There was also a remnant of what appeared to be a Christmas tree light bulb attached to the wires.

The FBI lab in Quantico, Virginia, and the NYPD bomb squad are analyzing components of the explosive.

Ullah last visited Bangladesh in September to see his wife and newborn son, relatives and police told The Associated Press. He left them both behind when he returned to the United States, the AP reported.

Ullah’s family members in Bangladesh, including his wife and her parents, were taken in for questioning by counterterrorism police in Dhaka, the capital, according to Bangladeshi government officials.

The Embassy of Bangladesh in Washington said in a statement Monday, "Government of Bangladesh is committed to its declared policy of 'Zero Tolerance' against terrorism, and condemns terrorism and violent extremism in all forms or manifestations anywhere in the world, including Monday morning's incident in New York City."