Updated

A federal judge has told a Nigerian man that he is charged with trying to blow up a Northwest Airlines plane on Christmas Day.

U.S. District Judge Paul Borman read 23-year-old Umar Farouk Abdulmutallab his charges in a conference room on Saturday at the University of Michigan Medical Center in Ann Arbor, where he is being treated for burns.

Agents brought Abdulmutallab into the room in a wheelchair. He had a blanket over his lap and wore a green hospital robe.

The judge asked Abdulmutallab if he understood the charges against him. He responded in English: "Yes, I do."

The judge told Abdulmutallab that he will be held until his next court appearance on January 8.

Abdulmutallab is accused of setting off a device aboard a Northwest flight upon landing in Detroit, which resulted in a fire and what appears to have been an explosion.

He was reportedly subdued and restrained by the passengers and flight crew. The airplane landed shortly thereafter, and he was taken into custody by Customs and Border Patrol officers.

Preliminary FBI analysis found that the device contained PETN, also known as pentaerythritol, a highly explosive device. FBI agents recovered what appear to be the remnants of the syringe from the vicinity of Abdulmutallab's seat, believed to have been part of the device.

Abdulmutallab required medical treatment, and was transported to the University of Michigan Medical Center after the plane landed.

A source tells Fox News that the suspect was granted a "multi-entry" visa to the U.S. last year, meaning that he could essentially come and go as he pleases.

The source also says that Abdulmutallab has traveled to many European countries in the past year, possibly even Yemen.

Abdulmutallab's father reportedly told a Nigerian news outlet that six months ago he alerted the U.S. Embassy to his son's fanatical religious views, according to the New York Post.

The father, Alhaji Umaru Mutallab, allegedly told Nigerian newspaper This Day that he had informed both the U.S. Embassy and the Nigerian security services of his son's activities six months ago, the Post reported.

"This alleged attack on a U.S. airplane on Christmas Day shows that we must remain vigilant in the fight against terrorism at all times," Attorney General Eric Holder said.

"Had this alleged plot to destroy an airplane been successful, scores of innocent people would have been killed or injured. We will continue to investigate this matter vigorously, and we will use all measures available to our government to ensure that anyone responsible for this attempted attack is brought to justice."

Interviews of all of the passengers and crew of Flight 253 revealed that prior to the incident, Abdulmutallab went to the bathroom for approximately 20 minutes, according to the affidavit. Upon returning to his seat, the suspect stated that his stomach was upset, and he pulled a blanket over himself.

Passengers then heard popping noises similar to firecrackers, smelled an odor, and some observed Abdulmutallab's pants leg and the wall of the airplane on fire. Passengers and crew then subdued Abdulmutallab and used blankets and fire extinguishers to put out the flames.

Passengers reported that Abdulmutallab was calm and lucid throughout.

One flight attendant asked him what he had had in his pocket, and he replied "explosive device."

Earlier Saturday, it was revealed the U.S. reportedly had known for at least two years that the suspect could have terrorist ties.

The official said that the suspect has been on a list that includes people with known or suspected contact or ties to a terrorist or terrorist organization.

The intelligence database that Abdulmutallab is part of is described as containing people who have "loose ties or links to extremists," Fox News has learned. Any person in this database is someone who as of yet rises to threat level of no-fly lists or other more serious screenings.

Multiple law enforcement officials identified Abdulmutallab as a Nigerian national who was reportedly an engineering student at London's University College.

On Saturday, police in the U.K. were searching a number of locations in connection to the suspect, while authorities met with a Nigerian banker that may be the father of the suspect.

Former bank official Alhaji Umaru Mutallab says he traveled from his home in the Nigeria's Muslim-dominated north to meet officials in Abuja, the capital. The elder Mutallab says his son left London to travel, though he did not know where to.

"I believe he might have been to Yemen, but we are investigating to determine that," Alhaji Umaru Mutallab said.

Abdulmutallab's family is reportedly wealthy and his apartment is in an upscale building.

U.S. Intelligence is looking into the claims of a connection to Yemen but so far there is no information of a direct connection.

Officials claim the suspect has links to Al Qaeda and are working with London Metropolitan police to search addresses with possible connections to the suspected terror attack.

A spokeswoman for Scotland Yard said that U.K. police are in contact with U.S. authorities and that searches are being carried out at addresses in central London. She refused to confirm the number and location of the searches.

An intelligence official said Abdulmutallab was being questioned and treated in an Ann Arbor, Mich., hospital. The hospital said one passenger from the flight was taken to the University of Michigan Medical Center in Ann Arbor, but referred all inquiries to the FBI.

Melinda Dennis, who was seated in the front row of the plane, said the man involved was brought to the front row and seated near her. She said his legs appeared to be badly burned and his pants were cut off. She said he was taken off the plane handcuffed to a stretcher.

Abdulmutallab's alleged U.K. links have also led to heightened security at airports and on all flights to the U.S. from Britain, the London Times reports.

A Department for Transport spokeswoman said, "In response to events in Detroit the US authorities have requested additional measures for U.S.-bound flights.

“We are monitoring the situation and will make any assessments as necessary as this develops.”

Although general airport security remains the same, with no change to luggage and liquid restrictions, passengers travelling to the US can expect increased searches at the gate before boarding.

The incident was reminiscent of Richard Reid, who tried to destroy a trans-Atlantic flight in 2001 with explosives hidden in his shoes, but was subdued by other passengers.

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The Associated Press contributed to this report.