Tunisian national Ahmed Abassi was charged with fraudulently applying for a visa in order to remain in the U.S. to facilitate an "act of international terrorism."

Officials said Abassi, who previously lived in Canada, travelled to the U.S. in mid-March, where he was arrested on April 22. He appeared before a judge May 2 and pleaded not guilty.

"Ahmed Abassi had an evil purpose for seeking to remain in the United States -- to commit acts of terror and develop a network of terrorists here, and to use this country as a base to support the efforts of terrorists internationally," said Preet Bharara, U.S. Attorney for the Southern District of New York.

"Thanks to the extraordinary vigilance of our prosecutors and law enforcement partners, Abassi has been thwarted and is being prosecuted for his alleged crimes."

Two Canadian residents -- Raed Jaser, 35 of Toronto, and Chiheb Esseghaier, 30, of Montreal -- already face terrorism-related charges in what the RCMP have called a plot guided and supported by al-Qaida elements in Iran.

Details of Abassi's arrest and charges were detailed in a release jointly issued by the U.S. Attorney's Office, the FBI and the New York Police Department on Thursday.

It said Abassi met with Esseghaier in New York City.

"Esseghaier, who was recently arrested in Canada and is currently incarcerated there on terrorism charges, was previously radicalized by Abassi," the release said.

"Abassi discussed his desire to engage in terrorist acts against targets in the United States and other countries, and his intention to provide support and funding to organizations engaged in terrorist activity."

The FBI alleged Abassi was unaware that one of his associates was an undercover FBI agent who was privy to the details of the terror plot. Authorities said Abassi was under constant surveillance while in the U.S.

They also alleged Abassi told the FBI undercover officer that he knew of a number of individuals who, like him, would be willing to engage in terrorist activity.

"Abassi made clear that he wanted to obtain immigration documents and to remain in the United States so that he could engage in 'projects' relating to future terrorist activities, including recruitment," the release said.

Details on Abassi's case came after an indictment and other documents were unsealed in Manhattan federal court Thursday.

The indictment charges Abassi with two counts of knowingly making false statements in an application to the immigration authorities for a green card and work visa in order to facilitate an act of international terrorism.

Each count carries a maximum term of 25 years in prison.

The RCMP said Thursday that it had worked "very closely" with the FBI.

"The FBI's parallel investigation has led ultimately to the laying of charges against the individual in the US," said Sgt. Greg Cox. "Through our efforts, we assured that at no time did this individual pose an imminent threat to public safety in Canada."

Cox added that authorities wouldn't be providing further details on any of the three men arrested in connect with the plot as their cases were before the courts.

Canadian authorities have said that those accused in the train terror plot had the capacity to carry out an attack, but there was no imminent threat' to the public.

The RCMP has also said there was no reason to think the planned attacks were state-sponsored by Iran.

Meanwhile, Via Rail said Thursday it's contemplating whether to ask all of its travellers for identification as it considers ways to improve security.

Transport Canada said it expects railway organizations to make appropriate threat assessments and develop measures to prevent problems.