Leaked documents from the Canadian Security Intelligence Service (CSIS) show that the intelligence service is far more concerned with Islamic terrorism behind closed doors than the left-wing Trudeau government will admit in public.

One of the documents, a report from a committee hearing in October of 2016, states: “The Service has never before faced a terrorist threat of the scope, scale and complexity of Sunni Islamist-inspired terrorism,” Canadian newspaper Sun News, which obtained the documents, reports.

Canadian Islamic radicals returning from fighting for jihadist groups in the Middle East have become a source of concern for CSIS, which says: “Extremists returning to Canada have the potential to pose a significant threat to our national security.”

One of the documents quotes a CSIS officer who said: “I should point out that we remain concerned about the number of individuals that we are not aware of, or about whom we have incomplete information, due to the significant operational challenges associated with such investigations.”

The comments are in sharp contrast to the Liberal government of Prime Minister Justin Trudeau which has largely downplayed the terror threat from returning radicals.

Trudeau provoked widespread criticism last month after he commented that returning fighters “can be an extraordinarily powerful voice for preventing radicalisation in future generations”.

While the Liberal government has focused on deradicalisation, announcing plans to use “poetry and podcasts” to do so, CSIS warns that “Returnees may respond in a number of different ways – from returning to regular life, radicalizing others, or financing and facilitating the travel of others, to attack planning.”

The Trudeau government has not released current figures on how many Islamic radicals have returned to Canada with Public Safety Minister Ralph Goodale claiming in November that 60 or so had come back to Canada, though the figure was pointed out to be two years old.

One man, who had previously been a member of the Islamic State terror group and served in their religious police force, was interviewed by Canadian broadcaster Global News in September. He brushed off his involvement with the terror group saying: “We all do things that we regret … All that’s behind me.”

Since the 2015 general election, the Liberal Party has become known for championing Muslim causes. Recently, Prime Minister Trudeau caught flak for making a public statement about an alleged attack on a girl wearing a hijab that turned out to be fake.

Liberal MP for St. Catherines Chris Bittle also received criticism after he referred to anti-Islamic State protestors as “white supremacists”.