GREENBELT, MD. -- Former Canadian army reservist and accused white supremacist Patrik Mathews was denied bail during an appearance in a U.S. court on Wednesday, where he is facing several firearms charges amid allegations of wanting to start a race war.

The bail hearing followed the 27-year-old's arrest last week, the culmination of what court documents indicate was weeks of covert FBI surveillance of his activities and those of other suspected members of a violent white-supremacist group called The Base.

Mathews is facing one count of transporting a firearm and ammunition with intent to commit a felony and one charge of being an alien in possession of a firearm and ammunition. Each charge carries a maximum of 10 years in prison, three years of probation and a $250,000 fine.

Court filings entered by prosecutors ahead of the bail hearing indicate Mathews and two other men, both of them U.S. citizens who were arrested at the same time as he was, were being watched and listened to by American investigators for weeks before they were detained.

The observations were made possible in part by a hidden camera and microphone installed by FBI investigators in a Delaware residence where Mathews lived with one of his co-accused, 33-year-old Brian Mark Lemley.

Prosecutors allege the two disparaged Jewish people and African-Americans and discussed the planning of violence at a gun-rights rally in Virginia this past Monday. Mathews is also accused of having talked about derailing trains and sabotaging power lines "to bring the economic collapse."

Mathews also videotaped himself advocating for killing people and poisoning water supplies as part of a "violent revolution" based on race, prosecutors allege in the filings.

Mathews first made headlines in August when a report by the Winnipeg Free Press described him as a recruiter for The Base, which prosecutors in the U.S. have described as a militant white-supremacist group focused on perpetrating violence against ethnic minorities.

At the time, Mathews was a combat engineer with the 38 Canadian Brigade Group in Winnipeg, though the military said then it was investigating his alleged links to The Base and fast-tracking his request to be released from the Canadian Armed Forces.

The RCMP were also reportedly conducting their own investigation, though the Mounties have not confirmed the report. They had previously seized a number of weapons from a house in Beausejour, Man., about 60 kilometres east of Winnipeg, where Mathews lived.

A short time later, Mathews disappeared and his truck was found abandoned on a rural property in southern Manitoba near the U.S. border. The RCMP said it was treating his disappearance as a missing-person case.

Prosecutors have said Mathews crossed into the U.S. illegally, where he was picked up by Lemley and 19-year-old William Garfield Bilbrough. Both Lemley and Bilbrough, the third man arrested, are described as members of The Base. Lemley previously served in the U.S. Army.

On Jan. 5, Mathews and Lemley returned to the Delaware home from a gun range in Maryland and began packing rations and other material that investigators believe they planned to use during and after the Virginia rally, court documents say.

They packed containers with food and supplies before Mathews remarked about needing to bring a gas mask, investigators said. Lemley also said he thought they'd have food to last between three and five months and that it "might be enough til the war is over," according to the filing.

Lemley had also discussed loading the truck "for the war," the documents said. Authorities said Lemley had also bought a four-foot (about one-meter) metal antenna to attach to his truck to get a better radio signal to communicate after any Virginia confrontations.

A day before their arrests, Lemley told Mathews that "there cannot be no trust among a group of murderers," the detention memo says.

"I cannot trust you to keep my murdering secrets. Not under threat of 30 years in jail and torture. Why should I trust you?" Lemley asked.

"You realize that they're just going to call us terrorists," Mathews said minutes later.

As federal agents moved in to arrest Lemley and Matthews last Thursday, the men smashed cellphones and dropped the pieces in a toilet, a prosecutor said.

Bilbrough was arrested in Maryland. Prosecutors say Bilbrough has repeatedly expressed an interest in travelling to Ukraine to fight alongside "nationalists" for several months.

The Anti-Defamation League says members of The Base and other white-supremacist groups have frequently posted online messages advocating for "accelerationism," a label far-right extremists "have assigned to their desire to hasten the collapse of society as we know it."

Last Friday, Georgia authorities announced that they arrested three other members of The Base on charges they conspired to kill members of an anti-fascist group. The arrests came after an undercover FBI agent infiltrated the group and participated in shooting drills in the mountains of northern Georgia, according to a police affidavit.

The same document says the Georgia group met with a Base member who'd entered the United States illegally, though it doesn't name that man. It says that the Georgia men talked about killing him because he knew too much about their own plot.

Separately last Friday, the Justice Department charged a Wisconsin man who they say was also a member of The Base. That man is accused of spray-painting swastikas, the group's symbol and anti-Semitic words on a synagogue in Wisconsin in September.

This report by The Canadian Press was first published Jan. 22, 2020.

-- with files from The Associated Press