Najibullah Zazi,. seen in Denver on Sept 17, appeared in court on Monday on charges of lying to authorities in a U.S. terror investigation. ((Ed Andrieski/Associated Press))

An Afghanistan-born Colorado man who allegedly hand-wrote bomb-making instructions and who authorities say played a direct role in an alleged terror plot will be held until Thursday for a detention hearing.

The government is expected to oppose the bail release of Najibullah Zazi, one of three suspects who made court appearances Monday, during that hearing.

The men face charges of lying to authorities in a continuing terror investigation. If convicted, they face eight years in prison.

Zazi and his father, Mohammed Wali Zazi, 53, who were arrested in Denver on Saturday, appeared in court dressed in street clothes and handcuffed. Najibullah Zazi spoke little during the court hearing Monday except to say, "Yes," when asked whether he understood the charge against him.

Mohammed Zazi is expected to be released in the next 24 hours. Prosecutors said they would not oppose his release if he's electronically monitored at his home, something his court-appointed attorney agreed his client would do.

His son Najibullah, a Colorado airport shuttle driver, has admitted receiving weapons training from al-Qaeda.

According to court documents released Sunday, authorities claim he played a direct role in the alleged terror plot, although officials have said they don't know the timing or location of any planned attack.

Investigators said they found notes on bomb-making that appear to match Zazi's handwriting and discovered his fingerprints on materials — batteries and a scale — that could be used to make explosives.

A third suspect, Ahmad Wais Afzali, 37, was arrested in New York, where he is an imam at a mosque in Queens.

Afzali appeared in federal court Monday in Brooklyn and was ordered held without bail. His attorney, Ron Kuby, said he would seek bail Thursday.

Laptop had bomb-making notes: FBI

Federal prosecutors say Zazi admitted to FBI agents that he received instruction from al-Qaeda operatives on subjects such as weapons and explosives. They also say he received the training in the federally administered tribal areas of Pakistan.

Court documents filed in Denver say Zazi spoke with agents under an agreement where he might avoid prosecution. Zazi's defence attorney denied reports that he had considered a plea deal related to terror charges.

The FBI said it found images of handwritten notes on a laptop containing formulas and instructions for making a bomb, detonators and a fuse. Zazi told the FBI that he must have unintentionally downloaded the notes as part of a religious book and that he deleted the book "after realizing that its contents discussed jihad."

An affidavit says the handwriting on the notes appeared to be Zazi's. It also says they were e-mailed in December as an attachment between accounts believed to be owned by Zazi, including an account that originated in Pakistan.

With files from The Associated Press