(CNN) -- A Tunisian, who authorities believe radicalized one of the suspects held in Canada on charges of plotting to blow up a passenger train, has been arrested in New York on unrelated counts, according to authorities who said he wanted to commit acts of terror in the United States.
Ahmed Abassi was arrested last month and charged in a newly unsealed indictment with two counts of making false statements to immigration authorities while applying for a work visa and green card.
"As alleged, 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, the U.S. Attorney for the Southern District of New York.
Much of the discovery in the case originated from recordings between Abassi and an undercover agent who spoke Arabic. They still must be translated and much of the material remains classified, prosecutor John Cronan said.
In court documents, prosecutors allege Abassi radicalized Chiheb Esseghaier, who then allegedly traveled overseas for training and plotted "to engage in terrorist activity in the West."
Esseghaier was arrested in Canada in April in a high-profile terror case. According to a U.S. intelligence official and another government official, Esseghaier, 30, of Montreal and another suspect plotted to put explosives under a trestle and set them off after a passenger train crossed from the United States into Canada.
Abassi previously lived in Canada, traveled to the United States in mid-March and was under surveillance by law enforcement until he was arrested on April 22, said prosecutors.
He allegedly met with Esseghaier in New York City. A man who neither Abassi or Esseghaier knew was an undercover officer also was present during their discussions and secretly recorded the conversations, said the government.
During the meeting with Esseghaier, Abassi allegedly "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, including the al Nusrah Front," according to a letter prosecutors wrote to a federal judge.
The al Nusrah Front is an organization commonly referred to as al Qaeda in Iraq. Abassi also allegedly said he wanted to recruit other like-minded people for acts of terrorism.
The letter adds that Abassi told the person he didn't realize was an undercover officer that Esseghaier's plans were good but the timing for them was not right.
Abassi allegedly said he had a plan involving "contaminating the air or water with bacteria in order to kill up to 100,000 people" but he said Esseghaier was dismissive.
The documents do not specify whether Abassi had a location in mind for such an attack.
Abassi allegedly discussed with the undercover officer his plans to obtain immigration documents fraudulently so he could stay in the United States and engage in terrorism, and his plan included a claim that he was working for a company owned by the undercover agent.
The documents did not say whether Abassi knew of the foiled Canadian rail plot.
Albassi appeared in federal court in New York Thursday. Each of the two charges against him carries up to 25 years in prison.
CNN's Gloria Borger, Paula Newton and Pam Benson contributed to this report.