A second man accused in a Canadian terror plot appeared at a hearing Wednesday as authorities continue to gather information about the plan they say would have caused untold death and destruction.

Chiheb Essegheier, 30, was arrested in Montreal for allegedly planning an al Qaeda-backed attack on a passenger train, authorities said. His next court date has been set for May 23.

Raed Jaser, 35, his suspected accomplice, had a separate hearing in Toronto on Tuesday.

After waiving the reading of his charges, Jaser returned to the Canadian federal facility where he's being held. Bail was not considered in his case.

The suspects planned to target a train crossing from the United States into Canada, according to a U.S. intelligence official and another government official.

It was aimed at the New York-to-Toronto line that runs through Buffalo, another U.S. official said.

Once the explosives went off, two of the officials said, the train would have careened off its tracks, causing major destruction.

The attack never happened.

Instead, the suspects are behind bars after the Royal Canadian Mounted Police announced their arrest Monday.

Jaser is "in a state of shock and disbelief," his lawyer John Norris said after his court appearance. He said his client is a permanent resident in Canada and has lived there for 20 years.

"He is anxious to see the evidence that the (government) says that it has against him," Norris said Tuesday.

Both suspects face charges of conspiring "to murder persons unknown ... for the benefit of, at the direction of, or in association with a terrorist group," court records show.

Who are the suspects

Authorities have not released much detail about the men, including their nationalities or how long they'd been in Canada, beyond that they were not Canadian citizens.

University of Quebec spokeswoman Julie Martineau said Essegheier has been a doctoral student at the school since 2010.

He was a student at the National Institute of Scientific Research and was conducting research on nanosensors, which are used primarily for medical treatments or to build other nanoproducts, she said.

The suspects watched "trains and railways in the greater Toronto area" and intended to derail a passenger train, said Royal Canadian Mounted Police Chief Superintendent Jennifer Strachan.

The Canadian Broadcasting Corp., quoting "highly placed sources," reported that both had been under surveillance for more than a year.

White House spokesman Jay Carney said the FBI worked with its law enforcement counterparts in Canada, its close ally, during the investigation.

The terror plot, which a Canadian police official said on condition of anonymity wasn't linked to last week's deadly Boston Marathon bombings, was in its planning stages and not imminent.

Still, the outlines are reminiscent of those found in a document seized during the raid that killed Osama bin Laden in Pakistan.

The document indicated that al Qaeda members discussed as early as 2010 a plan to derail trains in the United States by placing obstructions on tracks over bridges and in valleys, though no specific rail system was identified, a law enforcement official told CNN in 2011.

Authorities have said that they believe the suspects had help.

The men got "support from al Qaeda elements in Iran" to carry out an attack and conspire to murder people in greater Toronto, said James Malizia, assistant commissioner for the Royal Canadian Mounted Police.

There's no evidence that the Iranian government was behind the plot, he added.

"When I speak about 'supported,' I mean direction and guidance," Malizia said.

Iran denies that al Qaeda has any presence within its borders.

Iranian Foreign Minister Ali Akbar Salehi told Iran's state-run IRNA news agency that the allegation is "the most ridiculous thing," he has ever heard.

CNN's Gloria Borger, Pam Benson, Catherine Shoichet, Jack Maddox, Tim Lister, Wolf Blitzer, Steve Almasy, Paula Newton, Irving Last and Mayra Cuevas contributed to this report.