Twin brothers from Ottawa have both appeared in court on several terrorism-related offences, including one charge of trying to leave Canada to "participate in terrorist activity abroad."

Ashton Larmond and Carlos Larmond each face multiple charges after they were arrested Friday by the RCMP.

On Saturday, a former minor hockey teammate and the brothers' lawyer confirmed the two men are twins and CBC News learned they both attended Rideau High School in Ottawa.

Carlos Larmond was arrested at Montreal’s Trudeau airport as he was "intending to travel overseas for terrorist purposes," RCMP said in a release, while Ashton Larmond was arrested in the Ottawa area.

Ashton Larmond is charged with:

Facilitating terrorist activity.

Participation in the activity of a terrorist group.

Instructing to carry out activity for a terrorist group.

Carlos Larmond is charged with:

Participation in the activity of a terrorist group.

Attempting to leave Canada to participate in terrorist activity abroad.

Twins allegedly conspired over a 5-month period

According to court documents, the twins allegedly conspired from Aug. 1, 2014 to Jan. 9, 2015 in both Ottawa and Gatineau, Que.

Both appeared in court briefly, but separately on Saturday morning via video from the Ottawa police cellblock. They were ordered not to communicate with each other while in custody at the Ottawa-Carleton Detention Centre.

Carlos wore a bluish-grey hoodie with closely cropped hair and a bushy beard, while Ashton wore a dark, long sleeve shirt and had a bushy beard, the CBC's Ashley Burke reported.

The Crown said Carlos has an outstanding charge in Gatineau, while Ashton has a criminal record but no outstanding charges. Both men, who are practising Muslims, were known to Ottawa police.

Outside the Ottawa courthouse, defence lawyer Joseph Addelman said the charges strike at the heart of Canadian democratic principles.

Defence lawyer Joseph Addelman spoke on Saturday, Jan. 10, 2015 as he represented both Larmond twins after the Ottawa brothers were charged with terrorism-related offences. (CBC) Addelman said. "My clients intend to vigorously defend these allegations. This is going to be a case where we are going to determine how much value the Canadian system truly places on freedom of expression, freedom of assembly, freedom of religion,"said.

"All Canadians have the right to express their religious beliefs and to participate in free assembly without that being a criminal offence."

RCMP declined to offer any further details on the investigation or the charges, which carry a possibility of life in prison. RCMP did brief Public Safety Minister Steven Blaney about the arrests, according to the minister's spokesman.

"We continue to confront and address the significant challenges posed by high risk travellers who may wish to go abroad to support or engage in terrorist activities," Blaney said in a statement.

The case was adjourned until Feb. 12 when the twins will once again appear in an Ottawa court via video. Addelman said each brother will have his own lawyer in a couple of weeks.