Two 18-year-old Montreal students have been charged with several terror-related offences following their arrest last week.

The news comes on the same day the director of Canada’s spy agency told a Senate committee of a sharp increase in the number of Canadians participating in terrorist activities.

El Mahdi Jamali and Sabrine Djaermane are accused of attempting to leave Canada to commit a terrorist act abroad, possession of an explosive substance, facilitating a terrorist act, and committing an act under the direction or for the profit of a terrorist organization.

Jamali and Djaermane briefly appeared in a Montreal courtroom on Monday and pleaded not guilty.

Prosecutor Lyne Decarie told reporters outside the courtroom that “investigative moves” in the past few days brought forward enough evidence “to get the consent of the Attorney General to have these charges.”

The two College de Maisonneuve science students were arrested last week, in what RCMP described as a "preventive measure."

On Monday, the RCMP said it had acted on a tip from the public, and that explosives had been found at the home of one of the teens.

Officials did not say which terror organization Jamali and Djaermane were allegedly in contact with or where they might have been headed.

The young men will remain behind bars until a bail hearing, currently scheduled for Friday.

Earlier this month, two other Montreal residents signed peace bonds that require them to relinquish their passports and avoid contact with terror groups overseas. At the time, RCMP said they feared Daniel Darko and Merouane Ghalmi posed a risk to commit terror offences.

Five other College de Maisonneuve students are believed to have fled the country to join Islamic State militants in the Middle East earlier this year.

Meanwhile, CSIS director Michel Coulombe told a Senate committee examining the proposed anti-terrorism act -- known as Bill C-51 -- that the threat from terrorism has never been greater.

Coulombe said the spy agency has seen a “steady increase in the number of terrorist travellers, including those who have travelled, have returned from travel or aspired to do so.”

Coulombe estimated the number of Canadians leaving for terrorist purposes in Iraq and Syria has increased by 50 per cent in the past three to four months.

In response to Monday’s charges in Montreal, Public Safety Minister Steven Blaney said the anti-terrorism act proves his government’s commitment to “confronting the terrorist threat at home.”

“I commend the RCMP for their continued vigilance towards keeping our streets and communities safe,” he said.

“I also wish to underscore the important public support, and thank the citizens who helped our national security agencies in this investigation.”

With files from CTV Montreal